First things first. That is a nice post.

how much work should people have to do to accommodate one determined troublemaker?

There isn't just one disfavored monk, there are many. However, one of them annoys more than the rest to the point it is considered unbearable. A solution, however, can work for everyone.

Of course, if that isn't worth the effort, or the idea of changing the way things are done (which has worked for well over a decade) is anathema, a single monk can be singled out. If so, deal with the issue for the one monk with a banning or something. Pick your poison.

it is a way to show the people in charge of the site (of whom I am not one) how many people are sick of it

That is an excellent point. I didn't think of that. Reputation is an indicator to the management, especially when a difficult choice may be in the offing. Although this would require due diligence in voting on the post and not the monk (making quick downvotes less valuable), it is still a decent indicator.

It should be noted that it would make the site exclusive to people who don't tick everyone else off. That is still intolerance (by definition), but understandable, especially if the main concern is that bad advice is being offered consistently and in enough quantity, where there is a real fear of damage via misinformation.

How long would it take before you admitted you needed to put a restriction on your "everyone is welcome" policy?

That might depend on how much anime i watched recently, where some supposedly righteous character never gets angry. :) But seriously, such a person would likely get a warning and then get banned.

That case is not really comparable because he is both causing damage to other people and cannot be ignored given just one general area.