When this topic comes up I'm always surprised by the flood of comments stating "well golly gee, I'm sure he's real sorry he raped and stabbed those girls, we just need to put him through some advanced reading courses then send him back on his way!" Followed by, "now if you think he should be punished for his actions well you're just barbaric and primitive and irrational".
Punishment is not irrational. It's a fundamental ethical standpoint. Mitigating factors should be weighed (mental health, IQ), but at the end of the day people need to face the consequences of their actions.