In inferring that's necessarily the case, one probably commits the fallacy of composition.

Most real-world communities involve such compromises, if only in the values of autonomy and freedom. We will gladly make these compromises given the attendant benefits, but this is not to say that a change in core values has not occurred.

Speaking of "Invoking this metaphor (and the instinct of protection which it naturally evokes)"...

You are misinterpreting my point. I'm not saying we should care about how a pure social club is managing itself. I'll even endorse such clubs calling themselves "online communities", if this makes folks happier. But the moment an "online community" is having harmful effects on the real world (say, by fostering misconceptions about economics and free markets [as per sibling thread], or by spreading lies such as "global warming is caused by solar activity, not by human beings"), is when respectfully engaging with that "community" becomes justified and praise-worthy. And so is criticizing them as "authoritarian" if they were to dismiss genuine grievances about their real-world impact with petty concerns about "politeness" and "manners".

This is part of the reason why Less Wrong discourages political discussion. We do not know how to have a genuinely useful/productive political debate online, and we don't want trolls to come here and complain about how their pet political cause is being handled. So we focus on the smaller problems of epistemic and instrumental rationality, leaving politics to specialized "open politics" websites which can experiment and take the heat for what they do. In turn, open politics folks will hopefully refer to Less Wrong for basic rationality stuff.