It ain't just retro, believe me. There may be a more... visible? part of it because a lot of them tend to trend older and thus will have some stodgy views (which I am not defending, to be perfectly clear), but it's any enthusiast community for nearly any product or set of media. The fighting game community has it, retro gaming community has it, gaming communities centered around more recent series do it (look at anything super popular, ie Overwatch), etc.
I wish there were more pushback against, say, retroarch devs for being complicit in doxxing and harassing people, to the point we lost near/byuu. The problem with it is that the stink isn't there if you don't stick around long enough to sniff it, so the "regular/casual/whatever" user has no idea what's going on and how shitty it is.