The use of “subhuman” in particular is fascist behaviour and I’d assume it is wreckers rather than longstanding members, it’s not language that socialists are fond of.

That’s not true at all. Look at any post about landlords or Zelenskyy or “bourgeoisie”. Count the number of pictures or references to guillotines.

I’ve already personally blocked the whole instance because it’s not worth arguing with people over and over.

Edit: you can see from the comments below what I’m talking about. I don’t care who these people think “deserve” the label of “subhuman”. I don’t want to interact with people who talk like that or think like that. That’s why I block them all.

I don’t know if defederation is the answer, but this instance is clearly a haven for these people. So I have already taken action.