I do think there's a want/need for Threads to be "okay" on Fedi because if Facebook can be redeemed then anyone could. There's this thing though where there's a collective push to redeem violent folks without doing any work to address their violence (if not mitigate it). This is the case with some social predators (sexual, finanical, etc) and it's clearly the case here.
Using the people stuck (and that's what they are: stuck) on Facebook as a sword to defend the moving of Facebook to fedi is lazy at best.