This has happened once before and they reversed it. But they said this last time too:
The discussions that have happened in various threads on Lemmy make it very clear that removing the communites before we announced our intent to remove them is not the level of transparency the community expects, and that as stewards of this community we need to be extremely transparent before we do this again in the future as well as make sure that we get feedback around what the planned changes are, because lemmy.world is yours as much as it is ours.
Idk about ani.social but the other two are. Ani.social has a general anime discussion community that was created as a replacement for the anime community on lemmy.ml and has rapidly surpassed it in activity. You’re not allowed to link !anime@ani.social on lemmy.ml either.
Lemmy.ml admins would argue they host loli/pedo content, but ani.social would argue it’s just mainstream anime content and it’s part of the genre. I don’t really know more than that, but I think it’s a bit unfair to describe the whole ani.social server as being used for porn.