The history of mtgox is not that simple and it is somewhat difficult to say who actually was the guilty one. Maybe there was lots of incomptenece involved but I'm pretty sure that also in a situation like that it might be so difficult even think straight.
MtGox was actually developed by Jed McCaleb, and Karpeles (MagicalTux) later bought the business from Jed. At the time of the sale the exchange already had tons of issues and apparently missing 80k BTC. It was perfect timing for Jed, who later started Ripple. For Karpeles the biggest mistake was buying the business. I would consider the latter mistakes only a minor mistakes. I would guess the codebase/security/etc was quite a horrible as well, can't really blame MagicalTux for not managing to save that business.
https://www.newsbtc.com/2016/05/22/mt-gox-a-new-revelation-s...