Well, I would've certainly felt better knowing that the guy who robbed me got punished.
Note that we're talking about a justice system that rehabilitates vs. one that punishes. Do you care which one happens to the perp, with the knowledge that they will be back in society at some point?
Why do we have to choose between rehabilitation and punishment? The goal should be "If you did the crime, you will be punished, but while you're being punished, we can help you become a better person".