@aral I agree with @Gargron on this and I am not in favour of preemptive defederation.
The whole promise of the fediverse is that it can't be taken over, and this is a huge test to see how it works out when a big corporation federates.
Building up walls between us and millions of people makes no sense to me. I don't want to be part of a niche platform where some gatekeepers want all instances to do the same thing.
We'll see how Threads moderates. If it impacts us, we can defederate then