My answers to the questions in the title are "no" and "yes." I've been catching some flak today on my Facebook page because I blocked three Holocaust deniers and/or radical Catholic reactionary (RadCathR) Catholics. Some people tell me I can't do that: that it isn't Christian; that it violates "free speech"; in other words that I am supposedly obligated to spend my time interacting with any and every wacko, lunatic position imaginable.
My policy is clear; always has been from Day One online. It is expressed quite clearly in a post linked on my blog sidebar, and has remained essentially the same for many years. I don't moderate every comment on my blog and I virtually never ban people there, as I stated in this post. I even took a poll once on my blog about how to treat clear trolls. Here is what happened:
We just voted on the trolls issue. The "let them stay and ignore them" proposition won by a 62-38% margin. That's always been my policy, and now I know that 6 of 10 of my readers agree with it.
But I am sensitive to the other 40% too, who wanted to ban the trolls. They often gave very good reasons for their position on this matter, too. It seems to me that there is another level of annoyance and obnoxious, insufferable behavior that deserves immediate banning, above and beyond the troll issue. Everyone recognizes that a person coming and speaking rank vulgarities and profanities, should not be allowed free speech. And we all accept that the person who yells "fire!" in a crowded theater should be escorted out and even possibly charged with a criminal act.
Well, it seems to me that a similar line is crossed with people whose sole intent in coming onto this blog is to insult its host, who (as they know full well) has always let them speak up till now.
Thus, my one exception was someone who could only insult me on my blog, and do nothing else.
I also have more debates with all types of folks online than anyone I have ever seen (some 650 or so by now: I stopped counting some time ago). Of all the absurd charges I've had to put up with: the one that I am "scared" to debate or somehow wish to shut down free exchange of ideas is surely one of the most manifestly ludicrous.
But I have chosen (as a matter of time stewardship) to no longer attempt debate with some folks who have shown themselves persistently, relentlessly unable to engage in civil, constructive debate. Hence, I stopped attempting it with the fringe anti-Catholic wing of Protestantism in 2007.
On Facebook, however, it is necessary to follow a stricter guideline with regard to "free speech." I do not apply my usual (virtually unlimited) free speech advocacy there. The reason is simple: I have nearly 5,000 friends and my posts are all set to "public." This means that anything posted is seen by potentially a lot of people. Certain extreme, fringe, kooky folks are too extreme to warrant being granted any attention at all. Holocaust deniers would be among them. Neo-Nazis or Klansmen would be, too. I completely agree with what Simcha Fisher stated in an article in the National Catholic Register today:
. . . once you publicly deny the Holocaust, you are no longer allowed to say anything, about anything, ever. Shutting up: that's what's for you, from now on. The end, goodbye to you and farewell to thee.
I think belief in a flat earth or geocentrism fits into extreme kook category, too, though it doesn't involve a despicable hatred as these other views. I also will not countenance RadCathR Catholics (i.e., those who want to tear down the pope and Vatican II and the Novus Ordo ("New") Mass and can do little else.
No one is obliged to offer absolutely unlimited free speech on a Facebook page or a blog. This is immediately obvious to most people. For example, vulgar sexual talk is understood to not be allowed in Christian venues (and even, for the most part, in secular venues). That's understood. It's a limit; it takes away so-called "rights" for people to say anything they want, of this nature, in public. It may no longer be the case on TV and in the movies, but it is on Christian Internet sites. The classic instance of such a limit is yelling "fire" in a crowded theater.
My purpose on my Facebook page and blog is to be a Catholic teacher and apologist. I want as many people to visit and read as I can get, and I want them to feel that it is a congenial place, minus all the rotgut and fighting and sheer nonsense that is so prevalent on the Internet. I want it to be different; an example of what discussion can be online if people cultivate an atmosphere for it to take place; applying a higher standard. Many thousands are completely fed up with the Internet and the low level of discourse that is so widely found. I hear the complaints all the time.
Also, one must distinguish between debating someone in some neutral place vs. the same person coming in and commenting in an obnoxious manner, or trying to dominate (trolling) on a Facebook page, which is one's own "territory" or domain. It's akin to an unwanted person coming in and dominating a party in your home and offending lots of people there. No one is obliged to entertain such a person indefinitely under the guise of so-called "free speech." Crucial distinctions must be made in this regard.
The only way to create a good atmosphere for discussion and learning (in Facebook) is to block the wackos (or defriend them if posts are "friends only"). Its really that simple. It's not ideal (in a sense), but it's the only practical way to do it. Nor is there anything in the slightest bit "wrong" or "unjust" about this. People can get to a place (because of fringe, extremist notions) where they aren't welcome in venues where thoughtful, conscientious people gather to engage in constructive, civil, charitable discussion about issues.
Now, here are some exchanges today on this issue from my Facebook page. my debate opponent's words will be blue.
[after blocking three Holocaust deniers and/or RadCathRs] These goofballs have free speech on their own pages. They don't have the "right" to be idiots and scumbags on my page. I have quality control. It's why people are comfortable here. They know we have adult Catholic or otherwise Christian conversation, minus insults and nonsense.
Most "deniers" are actually "revisionists", people who believe the numbers remain inflated. Shall we make pariahs of Catholic "Inquisition Deniers", who downgrade the numbers of people killed in the Inquisition from 200 millions over 200 or so years to something much smaller? Shall we shun the Stalin-purge deniers--I read one several months ago, by a New York Times commentator I believe, who cut the estimated number of dead under Stalin to about 5% of the usual number.
In any case, this practice of cutting off dialogue and conversation with reasonable people who happen to hold theories you disagree with is un-Christian. It is anti-Catholic. It is un-American. And it is illiberal. The Christian, the American way of things is to lay out ones case, to hear out the other side in a reasonable respectful dialogue--putting aside so far as possible any emotional investment in the discussion--and go forward from there. And holding minority views, eccentric views,even unpopular, eccentric minority views on one topic never renders one's opinions on some other subject invalid. Or reduces one to the status of pariah. Christians know no pariahs. Not ever. Not nowhere. Not nohow.
Holocaust deniers or minimizers or belittlers (choose your term) are not reasonable. Not ever. Not nowhere. Not nohow. This is most of the point!
As to the rest of your analysis, in my opinion you put Americanism and absolute free speech ideals: that come more from the so-called "Enlightenment" than from Christianity (even though those guys guillotined prominent scientists rather than give them free speech) above biblical teaching. You seem quite unfamiliar with the abundant biblical teaching in this regard.
St. Paul repeatedly urges Christians to not associate with (or separate from) divisive, sectarian-type folks:
Romans 16:17 (RSV) I appeal to you, brethren, to take note of those who create dissensions and difficulties, in opposition to the doctrine which you have been taught; avoid them.
1 Corinthians 5:11 But rather I wrote to you not to associate with any one who bears the name of brother if he is guilty of immorality or greed, or is an idolater, reviler, drunkard, or robber -- not even to eat with such a one.
2 Timothy 2:23 Have nothing to do with stupid, senseless controversies; you know that they breed quarrels.
2 Thessalonians 3:6 Now we command you, brethren, in the name of our Lord Jesus Christ, that you keep away from any brother who is living in idleness and not in accord with the tradition that you received from us.
Titus 3:9-11 But avoid stupid controversies, genealogies, dissensions, and quarrels over the law, for they are unprofitable and futile.  As for a man who is factious, after admonishing him once or twice, have nothing more to do with him,  knowing that such a person is perverted and sinful; he is self-condemned.
St. Paul's advice to separate was not written only to bishops. He was writing to the Roman and Thessalonian and Corinthian congregations. Romans, for example, is written "to all God's beloved in Rome" (1:7); 1 Corinthians "to those sanctified in Christ Jesus" (1:2). Thus his recommendation / command to "avoid" difficult, contentious people is a general one in application: it applies to all Christians by logical extension.
When writing to the Corinthians above, Paul is scandalized that a serious unrepentant sinner had not already been removed by the assembly. He noted that he had told them to remove such a person, but they hadn't done so. But they can make that call. Paul gave the general teaching: "not to associate with any one who . . . " They apply it specifically to individuals.
Excommunication and anathematizing is perfectly biblical and Christian:
Matthew 18:17 If he refuses to listen to them, tell it to the church; and if he refuses to listen even to the church, let him be to you as a Gentile and a tax collector.
1 Corinthians 5:1-5 It is actually reported that there is immorality among you, and of a kind that is not found even among pagans; for a man is living with his father's wife. And you are arrogant! Ought you not rather to mourn? Let him who has done this be removed from among you. For though absent in body I am present in spirit, and as if present, I have already pronounced judgment in the name of the Lord Jesus on the man who has done such a thing. When you are assembled, and my spirit is present, with the power of our Lord Jesus, you are to deliver this man to Satan for the destruction of the flesh, that his spirit may be saved in the day of the Lord Jesus.
1 Timothy 1:19-20 . . . By rejecting conscience, certain persons have made shipwreck of their faith, among them Hymenae'us and Alexander, whom I have delivered to Satan that they may learn not to blaspheme.
Some things are so extreme and wicked that the person removes himself from reasoned, civil discourse. Simcha was exactly right in her article. This Holocaust stuff is one of them. If someone doesn't like it, they can lump it. Anyone is free not to participate in my discussions if they don't care for them, or for the "quality control" / moderation I exercise on my own page. It's perfectly justifiable according to the biblical teachings above.
We should absolutely debate ideas (and I do), except for the most extreme, wicked, idiotic positions that don't deserve the dignity of a response. Someone wants to debate Holocaust deniers? They can go right ahead. No one will prevent them from doing so. I am under no obligation to do so.
No one can tell me that I have to spend time countenancing wackos and extremists on my page. I have ample biblical warrant for not doing so. If someone else wants to do so, they can learn the hard way how many normal people will visit their page and participate.
[further lengthy comments from my friend]
And once again (as always so far), you have completely ignored all the Scripture I brought to bear on the topic. You want to go by fashion and secular libertarianism rather than Christian guidelines. Scripture is objective, inspired teaching. Your own opinions on this carry no particular weight (nor do mine). But God's revelation and Catholic tradition following it is entirely different.
Again, you state: "engaging those whose ideas we know to be wrong so long as they will engage us reasonably." But a Holocaust denier is anything but reasonable. Your assumption there is entirely debatable. Even your statement of it has a loophole a mile wide: "so long as they . . ." I say they don't do so, and we saw it in this very thread today.
All that said, you still have to ignore Paul's repeated injunctions to avoid unsavory people of many different types. At least you finally bring in some semblance of Bible teaching: Ultimately, we need to be like Christ, who made an apostle of a tax collector, received prostitutes and lepers as friends, and generally refused to give in to the impulse to make pariahs of others.
But you cite one motif in Jesus' actions while ignoring another. The same Jesus also stated:
Matthew 10:13-14 And if the house is worthy, let your peace come upon it; but if it is not worthy, let your peace return to you.  And if any one will not receive you or listen to your words, shake off the dust from your feet as you leave that house or town.
Stubborn people don't listen to the apostles; Jesus tells them to shake the dust off their feet and leave; not to keep engaging them forever out of some false notion of pseudo-"charity".
My biblical rationale for this remains unresponded to. It's diametrically opposed to what you are saying. Even your example of Jesus eating with sinners doesn't apply, because they were open to what He was saying, whereas Paul talks about those who are obstinate, contentious, divisive people who are deliberately being "oppositional."
We all have to conform to biblical teaching, and this one is quite clear. The only dispute is how to apply it. I say a Holocaust denier applies in spades, because he is a liar and is exercising the height of uncharity.
Jesus didn't spend time reasoning and being meek and mild with the moneychangers, either, did He? Here's what He did:
Mark 11:15-17 And they came to Jerusalem. And he entered the temple and began to drive out those who sold and those who bought in the temple, and he overturned the tables of the money-changers and the seats of those who sold pigeons;  and he would not allow any one to carry anything through the temple.  And he taught, and said to them, "Is it not written, `My house shall be called a house of prayer for all the nations'? But you have made it a den of robbers."