I have zero trust in Facebook and probably would not even believe them if Mark swore on his mother that they perform a proper wipe of your private data.

With that in mind you shouldn't have a hard time understanding why it sounds to me as if they delete all copies on servers in the EU but US mirrors of your profile remain untouched. How else could their algorithm deduct that your ladyfriend used to be a man without analyzing old conversations from deleted profiles. Could you live in a world where facebook sells birth controll pills to former biological males.

Ok I admit it's a hyperbole/edge case but I know that you know what I mean ;)