> It makes you wonder how these people get hired.

They must have forgotten to ask "Will you eventually lose our company billions of dollars in a bad derivatives trade?" in their interview process. It's easy to place blame on hiring someone after something like this happens, but would you have made the same criticism before the trade, when he had made the company lots of money? Interviews are imperfect. People change after you hire them. Etc etc.

Edit: clarification