Big instances straight up defederating does run the risk of causing a mass migration like with Hexbear, throwing ultra mega instances like .world into further moderation turmoil.
So that’s a choice that has to be made with care, though not a terrible one in the long term so long as the short term repercussions can be handled.
In the meantime I like reccomending folks join small instances with a defederation list and mod team they like (like mine). 🙂