The interesting aspect of these hacks, while they are horrible events for those who are affected, is that they make sure that a lot of coins are taken out of circulation, because as you also pointed out, there is very little incentive to have them be sent to a centralized exchange with the risks of losing these coins.
Outside of the initial market shock, it reinforces demand too. People who lose bitcoins in an exchange hack will want to reaccumulate their coins. So not only are the hacked coins being removed from circulation, but new demand (from old buyers) is being created too.