Wow that's pretty awful. I looked at the Fediseer listing for them and it turns out they've also been censured for lolicon and pedophillia.
So yeah they're pretty nasty. Good job keeping our communities safe from assholes like that.
What reason? I understand that there are moderation problems there but as it stands they're not super bad and can typically be handled by banning the users and communities from our instances. Defederation would be if there is a persistent cultural problem there (such as an instance with a dominating toxic atmosphere) or a large volume of spam users and communities, which so far doesn't seem to be a huge issue, at least not enough to warrant defederation.
Dream weasel is from shitjustworks. Looks like they're just memeing and/or doing that "I don't like furries and want the world to know about it" thing.
Of course he does, this is [email protected], this guy obviously went out of his way to do this, I can't imagine any other reason he would be subscribed or looking here.