I think the best path forward with Threads is not to defederate the whole thing, cutting off access to 10s of thousands of average well-meaning people, and instead defederate the rule-breaking, policy-violating accounts directly.
Again this is just my opinion and I'm fully in support of instance admins doing what they feel is best for their users.
I do ask that admins help inform their users about how to migrate their accounts if they see a need to move to another instance, and make some sort of formal announcement.