>This is like... the textbook definition of a hack.
Perhaps of "hacking FB", but he didn't "hack an account".
I don't see what the problems are for FB here. They have a moral obligation to reward him for reporting this bug, especially since their ToS are apparently not available in Arabic. Claiming that he showed any sort of malicious/inappropriate behavior is a really bad tactic to save some money when they clearly handled this very badly from the start, while his intentions were obviously good.
All they are achieving by reacting this way (including the apologets) is that next time, such people will just sell their exploits on the blackhat market.