These are the kinds of incidents that will lead to the fall of cryptocurrencies. These hackers are greedy, sure, but they don't realize that their actions are going to hurt them in the long run, as well, when all of this comes to a crashing halt
Come on man, every human being is this way. (there's a name for it) In the short run, they profit, in the long run, everybody loses. But if they don't profit now, others will take the quick buck and the original ones lose more.
It's how the world works.