I don’t have an issue with social media companies entering the Fediverse, at least on the surface, because it’s ultimately more users and it’s in line with the ideas of free exchange of information and content. My problem with it comes in when they try to buy instances, communities, or what have you. No one should have a monopoly on the Fediverse, and it shouldn’t be pay to win.
So, my answer is this: because no one can stop anyone from making their own instances, users decide whether to defederate their instances from Meta’s, or Twitter’s, or anyone else’s. Join an instance that doesn’t federate with Meta, or start your own if you have the know-how. Just like anywhere else on the internet, you don’t have to interact with content you don’t want to interact with.