Youthful indiscretion versus brazen criminal intent or indifference.
If I'm 12 and TP'ing a tree in someone's yard yes technically that is a crime, but it's not causing any major harm. A slap on the wrist and a few weekends of community service ought to scare you straight.
You start getting into murder, assault with a weapon, molestation or other wanton acts of disregard for human life, then you are a danger to society and should be locked away somewhere.
Isn't the criminal justice system already a form of institutionalized revenge? You commit a little crime, you get a little punishment in the form of a fine or probation. You commit a big crime, you're doing 25-life in a federal pound me in the ass prison.
I get what you are saying. What I am trying to get across (poorly I might add) is a line between something dumb you did because you weren't mature enough to think it through, as opposed to something premeditated.