We should'nt really discredit him just because of his trust. To me everything is possible with Mt.Gox.
A company that bit doesn't go bankrupt that easily. It maybe was Mark's bad managment but do you think that there wouldn't be someone there to advice him? Maybe he was trying to put blame on his "bad managment" by going public couple of times and wanting to show off a face persona to outshine the possible huge frauds that were going on under the name of Mt.Gox and made it go bankrupt.
But again, speculation.
According to the articles that I read after the Gox bankruptcy, Karpeles didn't trust any of his employees with the private keys of the cold storage wallets, which he kept locked in a safe at home. He was also spending most of his time coming up with cake recipes for his bitcoin cafe and worrying about his burgeoning waistline. At least that's what some of his former employees stated...