He was not an idiot, he was smart and manipulative. That's rather the opposite of an idiot. Assuming that he stopped being manipulative now that he's rich would be rather the stupid thing to consider. He's rich now because behaving this way has worked well for him.
>...an idiot while in college...
But "Young people are just smarter" -Mark Zuckerberg [1]
It's more than saying or doing something stupid. It is peek into a fundamental character trait of that person.
Good point. Why is anyone in prison? We should just let them all run free because we have optimism and faith in their ability to self-reform.
The question is not about a proper punishment for a crime, the question is whether a person still can do a good thing after he previously fucked up. People bring his previous silly actions as if it proves he can't do anything good. It simply doesn't.