Oh for heaven's sake...
Now we're doing the stupid pseudolegal "I don't consent to my content being used" thing here?
It wasn't legit when it was on any of the other platforms, and it's especially not legit on this platform where by posting something you are actively triggering a process by which the content is broadcast to others.
To declare that you don't consent to Meta getting your data really doesn't wash with this protocol that actively broadcasts it to them.
It's like yelling across your fence to your neighbor that you don't consent to his hearing you. You're the one yelling at him!
A distributed social network means even less control over where content goes.