Yes just few days back a exchange site ran away with appreciable amount of money. I think exchange sites come to loot user if they can't profit with their plans. But they should have little mercy on users hard earned money. Don't they feel insecure to run away with money if millions of people. I think exchange site have some rules and regulations and should be under registration of local police.
It's greed that make exchange owners/operators go full nuts.
Look at MtGox for example, it was back then the largest and most solid exchange before certain red flags were popping up about people not being able to execute withdrawals.
It was an exchange that was making more than decent profits at that time, plus the fact that Mark Karpeles had like 100K BTC already.
Why does someone with a great running exchange and a huge stash of coins go that far? Again, it's because of their greedy nature.
Their greed is so strong, that it overpowers their entire way of thinking and sense of being humane. It's really mind boggling.