We've already been over this. Bank robbery has a much harsher sentence than simple fraud. No matter his reasoning, the fact is, a crime was committed, and he needs to serve his time. The CEO probably took a plea bargain, too, which most likely lowered his sentence.
The scheme was already in place and running when the CEO took over. He wasn't the only person involved in the scheme and cooperated with authorities. There's no mention that I can find of the homeless man's prior record. Aside from past crimes, who's first thought is to rob a fucking bank when you need a few dollars? Anytime you commit a crime, no matter how small, there's a chance you'll be "made an example of" and get the maximum sentence they pin on you.
The more money you have, the smaller your time is.