The temptations to go nefarious must be incredibly strong when you're operating an exchange. Ultimately though it's a dim move. You can run now and fuck yourself for life or build a real business that might sell for way more than you steal. Unsurprising but still pathetic and loathsome especially to keep taking deposits when you know of the 'hack' for such a long time.
well they were only doing a maximum of 3000 volume at a 0.2%buy 0.3% sell (0.5% trade fee=15btc a day)
if you have over 40,000 coins and knowing that only 10% moves in or out at a time then yes stealing anything from 25%-90% is tempting for those without morals.
as oppose to running the exchange at 15 a day which would take 2 years to make 10,000..
so those without morals would easily see that taking 25% (10,000) and hoping the trading fee's can recoup that deficit in time to go unnoticed.
but it seems they got greedy and now want to keep the majority of coins