The need for punishment relates to the religious notions of carma and "getting what ou deserve."
We are a puritanical nation that values justice in black and white terms and only recognizes shades of gray when the offense occurs close to home. We need to rethink our systems of crimes and punishments. The basis of the term "correctional system" is to correct behaviors and guide an offender to a better way, not simply quarantine offenders for decades. For some reason we think that if we pass a law declaring that something shall not be allowed suddenly people will be aware of said law and never engage in the offending behavior.
That is not to say that we don't have shades of gray built into the system. We have simple violations, such as driving violations, that can result in the loss of a previously granted privilege. We have misdemeanors which are minor offenses that normally result in only monetary damages. We have major offenses with the result of fines, jail time and or probation. Then, we have 3-strikes-your-out laws that put away people for a lifetime for committing 3 felonies. There is very little offered for guidance
. Often it is don't you dare do that again
We are not using our existing system to the fullest (we like to make everything a felony punishable by incarceration) and we spend little money on crime prevention. Ignorance of the law cannot be used as a defense, but where is education about the law offered in any location other than a courtroom?