I'll probably get downvoted for saying this, but in general I think defederation is against the free software ethos.
Free software is supposed to be about giving control back to the user, not the BOFH that happens to run the server they are using.
There's obviously going to be exceptions for illegal content, or actively trying to disrupt the lemmy network (by DDOS, flooding, etc) but I feel that's where the line should be drawn.