Devil's Advocate: The possibility that there could actually be some sort of tampering, and that he actually is right. Afterall, the Bitcoin Foundation has /a lot more/ to lose than 500BnUSD if that's the case.
but the malleability doesn't steal in itself.. it is just like making fake receipts. Mt Gox still had to process the second withdrawal via customer service. There is no way that a business goes bankrupt from the returns counter unless everyone is in on it or it is just a weak coverup.
This scam runs deep and once the FBI is finally done with their SR investigation we may know a lot more on this... it seems there are a few combinations of scam going on. Karpeles has been in denial or complicit for a long time.. probably a bit of both
The the resend on the withdrawls where fully automated. No CS was involved.