If this is true, then if you try to make him feel culpability for his communication acts as usual, this will only make his fear stronger and make him more desperate to find a way out, and make him even more willing to break normal conversational rules.

I certainly wouldn't try to make him feel culpability. Or, for that matter, "try to make him" anything at all. I don't believe I have the ability to influence XiXi significantly and I don't believe it would be useful to try (any more). It is for this reason that I rather explicitly spoke in the third person to any prospective future readers that it may be appropriate to refer here in the future. Pretending that I was actually talking to XiXiDu when I was clearly speaking to others is would just be insulting to him.

There are possible future cases (and plenty of past cases) where a reply to one of XiXiDu's fallacious denunciations that consists of simply a link here is more useful than ignoring the comment entirely and hoping that the damage done is minimal.