It seems to me that the primary function is purely punitive and expends very little effort to rehabilitate anyone. Which stems from humans liking "just deserts

It seems to me that the primary function is purely punitive and expends very little effort to rehabilitate anyone. Which stems from humans liking "just deserts" and liking people to be punished for their crimes. A rational theory about deterrence, rehabilitation, and harm reduction may be more humane, but also difficult to implement and propagate through the populace. That being said, we humans are getting better at treating minority and animals.(Say, gay marriage is being legalized in more states) So I have some hope that our treatment of society's most unsympathetic and hated group better will improve as we become more rational and "nicer".