Though I haven't confirmed it (nor would I want to at this point), from my recollection of events, some community from burggit.moe was allegedly the source instance of the problematic images that were thought to have taken vlemmy.net down, which was reportedly some sexual depiction of young fictional cartoon/animal characters. This might not be illegal in some places but it definitely is in Ireland, so the server owner was notified as such and had most of their online accounts removed.

My Fedilore+drama post on it