i think the meaning of hack here is stolen from his wallet because i heard the news and even news from here which saying that his bitcoin is stolen by someone. i think its because from himself which is not careful to save the private keys and let other people know how much bitcoin he have. so this will attract other people to trying to steal his bitcoin and some of them is success to steal. we need to be careful to keep our private keys from other people and we need to save in the hidden place.