It doesn't prevent much in this particular case though. I closed my Facebook account some 12-13 years ago and I recently contacted them and asked to see what da

It doesn't prevent much in this particular case though. I closed my Facebook account some 12-13 years ago and I recently contacted them and asked to see what data they had on me (under the GDPR, because of shadow profiles). They absolutely refused to neither confirm or deny that they were building shadow profiles but kept repeating that if I didn't have an account, they didn't hold any data on me and then followed up by answering that if someone let Facebook rummage through their contacts and I was among them, then they'd of course hold that data until that someone decided to delete it... So, yeah...