As a general rule (and my not having explored too many fandoms, though I've heard stories...), I'd say the Buffy fandom is roughly about the middle of the large scale between friendly and extreme, generally speaking, and this board is the best one I've ever been on (and hadn't visited the Buffy forums for like 10 years before I came here, but back then I was the member of more than one).
I've noticed that with the rise of competitive blogs and vids that can be monetized (though some do it for the sheer infamy or somehow feeling smarter than an entire fandom), that many "troll videos" exploit algorithms to essentially get people angry (because that draws people in and keeps them coming back as well as reposting, which is also true of the news media in general). That is they're trashing it, or at least characters to such an extreme degree that it's bizarre.
Some of these have clearly not watched or read the material they're critiquing (or even making stuff up), and I can sometimes tell where they're skimming over in a rush just to exploit the algorithm while it's still popular (as opposed to those who have but have a wildly different interpretation than I do, but I can tell they generally love the series, at least at one time). I'm not sure how this has affected fandoms in general, but I'm sure it's for the worse.