This is a hot topic.

(Facebook is Meta, I dislike he brand washing)

1. Can we trust Facebook? I don’t
2. Should we block them from the get go? It’s a bit like guilty until proven innocent.
3. Shall admins sign a NDA for that? NO. (that seems to be controversial)
4. The example of “look Gmail didn’t break email, it’s still open” is actually bogus because Gmail has actually damaged email a lot by making it almost impossible to operate an email server. And other big like MSFT have followed. - in short it is possible that Facebook do long term damage. I don’t know how, but a big instance has more power than a small one. Like email servers.