Why do you think entire instances will be devoted to that? You will have to block every instance that has open registration, since any open instance cannot guarantee one of the people you mentioned will not come in. I guess the issue I have is that I see moderation as something between users and communities. Not that the overall instance should be doing the moderation.
Two separate issues are prompting “defederation”. Blocking users from posting to your local community and blocking remote communities from being mirrored on your server. Those should be handled differently. Beehaw didn’t want trolls posting mean things and blocked every user on a server. Your concern about illegal content would be more a complaint about specific communities that feature that content.
Either way you shouldn’t blame an entire server for a few users or communities you don’t want. Expecting everyone on a instance to be like minded isn’t going to work.
Federation/Fediverse should mean a user of any instance should be able to use any community. Gated communities shouldn’t be the expected norm. So, I would agree with the lemmy.world people who are upset at being broadly blocked from a Fediverse community. But it doesn’t matter because beehaw says it is temporary.
I wonder if he knows about the game Xcom