Sure but that doesn’t mean your instances should just hand your posts over to Meta??? And other people here are wrong, maybe lemmy does it differently, but on Mastodon when you defederate from an instance, your instance stops communicating with that instance entirely, rejecting all attempts to exchange information from that server. Anything the suspended instance saw before the suspension sticks around, but that’s basically it. If they never get a chance to even see the information, then the server essentially gets nothing.
My point is that the data on here is purposely shared with every other federated instance, there’s no semblance of privacy and your data is shared with hundreds or likely thousands of admins by the time it’s done (more and more as the network grows). There’s no reason to trust that every admin will keep that information private, some people are already talking about putting up services to expose all the hidden information (in the name of “transparency”). It’s simply trivial for Meta or anybody else to get copies of the data because there’s no real protection from it unless you’re making your instance an island (and that’s an island from everybody, not just one specifically known to be Meta).