I want to point out again that currently, Facebook offers no federated instance to defederate from. They've promised this in the future, and it may never happen, so it's all academic.

Also, I don't feel strongly about any of this. People are free to ignore me.

With that said, if Facebook did offer a federated product I would want to federate so I could see content from friends and family on that instance. Facebook can't harvest data or show me to ads on a different instance. If they tried to do something really stupid, like push ads to me through by posting them on behalf of my grandma, THEN I'd agree we should defederate, and most likely we wouldn't need to hold a vote, because the admins of this instance would just send out an announcement that Facebook is in violation of the instance's guidelines and has refused to correct behavior, so they're being defederated, as dictated by the defederation policy.

I think that's how it should work.