I don't think his decision to refuse surgery was a 'stupid decision', he was just being human. Steve's success in tech should not make him in the eyes of people be super human. Even in tech, successful people make lot of mistakes; history just records successes.
In the context of Kroft asking "how such an intelligent man could make such a seemingly stupid decision", human are naturally afraid of surgery, no want want their body open unless they have no choice; Steve too.
