You say “deactivate“ but Facebook does differentiate between deactivation and actual closing of an account. So if you merely deactivated it, then that would explain why your account was not actually deleted and it reactivated it for you.

> The biggest difference between deactivating and deleting a Facebook account is that deactivating your Facebook account gives you the flexibility to return whenever you wish, while deleting your account is a permanent action.

From what I remember, reactivation of a deactivated account merely requires logging back in. Which sounds like you did exactly that.

I wonder if deactivating, deleting etc means different things depending on local laws. Like I would expect them to have to allow full deletion in EU?

They do allow full deletion everywhere. But you must explicitly select it. If you choose to “deactivate” that is not actually closing the account. It is a dark pattern.