So we're all pro federation and decentralization, until we aren't... I think this is a very preemptive and paranoid measure, but thankfully it will work out just as the technology was built for, some will block, some wont, everyone will make their choice, and be happy in their corner of the internet.
That's disingenuous. It's not like Meta is some unknown party here with a clean reputation. They have a history, one that repeatedly shows they couldn't care less for the fundamental freedoms of the fediverse. Just like in society, for us to build free platforms where everyone is welcome, we must paradoxically not tolerate those that wish to wield the freedom of the platform against itself.
Except Meta by it's nature will aim towards Centralization. They're contradictive to the concept. It doesn't even take much thought to see the issue here.
Also as app_priori pointed out, Almost every instance already has a list of defederated instances.