YIMBYs have already done that for themselves, and are now in the advocacy phase.

Sure, but there's a ton of different groups that have already 'established for themselves' that they're right, and are in 'advocacy phrase'.

Every group has people who advocate for the group beliefs in emotional, close-minded ways. Groups that have accurate beliefs will also have people who argue more dispassionately.

If you see a discourse dominated almost exclusively by tribal back-patting, it should put their beliefs in question.

This article is specifically considering the question: are YIMBY ideas good? Why might they not be?