"The lesson here is once again that the safest way to store Bitcoin is in your own (preferably offline) wallet, and not on a website or exchange."
That certainly makes sense to me, but it must be hard or most people would do so.
Many (most?) of these people keep their BTC in these exchanges because they're constantly buying and selling it. They aren't interested so much in actually using Bitcoin as they are in making money from it.
They are gambling -- and they just lost.
seems you can't trust any online services, and its too difficult to maintain a safe system of ones own unless one is a security expert, so therefore it seems to me it is pointless trying to use bitcoin