I know who you're talking about, but do not share their name here.
If I am not speaking too boldly, there isn't really much the staff can do. The animations are user-made, they're not incorporated into the vanilla animations of the game by any means. That being said, it would be wrong for one to dictate what a fellow user can and cannot make. FeralHeart promotes creativity and grants the freedom for a user to add alterations to the game in whichever way they see fit, be it +18 or not.
The animations may seem disgusting for some but at least they're not FeralHeart's default animations, right? Don't download it if you do not want to witness that. It falls onto the judgement of the user whether or not they will obtain the download. That responsibility falls out of the staff's hands, again, if not speaking too boldly.