I just preemptively blocked the community for my account. I'd recommend everyone do the same until, and if they prove to be a problem.
I think instead of calling for pre-blocks or defederation of entire instances, we have to be vigilant and keep a close eye on the discussions going on around us.

I'm saying this not because I'm an "enlightened centrist" living in a delusion of tolerance or a fascist in disguise. I am as left leaning, antifascist, and antiauthoritarian as they get. I'm just saying this as I know from experience that there's no real way to eliminate people with bigoted views from our communities other than on an individual basis.

Ban an entire instance, you'll still have to block the individuals if they come one by one to stir shit up on your turf. Just skip the first part and go for the individual communities and users. They will simply find each other and form groups, as instances or otherwise anyway.

I know it's not ideal, but there's no real way to prevent these fascist groups from forming anywhere there's a large enough number of people. We can only block our own interaction with them and form counter groups, and actively fight against their bigotry.

I believe this is the sad truth we all have to live with, at least for the time being, because I can't see defederation as an effective tool.