to add on to what I said a few minutes ago,
I think it's ok for people to have avatars and such displaying these fandoms because that's what they support, and if you don't like that then just disable avatars or use that one greasemonkey script. I find people in animal suits humping strange too, but I don't get all personal about it because if thats what they wanna do, then I don't care about it (unless they're bragging/posing about it). If someone uses a pony/fandom picture as a reaction or general picture then it's okay unless they post them in every unrelated topic. But to prevent that I guess they should keep most of their fandom media in the desired topic so things don't get out of hand.