The more specific the higher amount of concentrated autism, i noticed it soon as i started joining forums in the mid to late 00s.
A general anime forum for example would be relatively normal with the discussion you expect, things start to get twisted when its about one specific show , more when its about one specific character, specific fetish, specific trope and so on.
This is actually bringing a repressed memory i had of these weird futanari forum i stumbled on when i was younger. The fucked up part that struck me is that the place was basically like sanctioned suicide but on steroids, any other discussion that wasn't about anime dickgirls was about commiting suicide, self harm, self hate and super edgy shit like that. In hindsight i realize i stumbled into a proto-trans snake pit. Of course at the time i couldn't make sense of it. This was around the same time i first got broadband, just the hentai stuff alone and people being opened about it like that was weird to me but then i just had to keep looking into the specific ones and get permanent brain damage, also around the time i discovered the gross side of Sonic.