It will be stolen again if they stay careless about it and that’s the simple case. However, getting the stolen bitcoin back is not going to be very easy. As long as you have the private keys you can play with the whole thing but when you don’t have it then you can just well wander around that’s all.
So your article says that it was a sophisticated hack of the exchange. Sometime I feel that these exchangers are doing all this in purpose so that they can claim the insurance. Is that a thing that’s possible really?