Transitive defederation -- defederating from instances that federate with Threads as well as defederating from Threads -- isn't likely to be an all-or-nothing thing in the free fediverses. Tradeoffs are different for different people and instances. This is one of the strengths of the fediverse, so however much transitive defederation there winds up being, I see it as overall as a positive thing -- although also messy and complicated.
The recommendation here is for instances to consider #TransitiveDefederation: discuss, and decide what to do. I've also got some thoughts on how to have the discussion -- and the strategic aspects.
Most of these ideas are ridiculous in how they desperately build up windmills to handle a surplus of lances among some fediverse users, but this genuinely applies the very thing you - completely out of nowhere - assume Meta would do to what you're doing: EEE.
You're trying to strong-arm users of AP into your modified version usage guidelines for it entirely to suffocate anyone disagreeing.
The good news is that none of the large instances are going for these insane policies. Small instances and solo instances can defederate themselves into irrelevance all they want, just like beehaw did.
exactly, they don't even have a definitive roadmap yet. most of the instances would block threads anyway if they ever make a decision that could EEE fediverse. blocking instances that federate with threads is kind of a bad move.