We are all well aware of the purpose of punishments: By punishing disobeying individuals, individuals who fear punishments will fear disobedience. And this is evidently an effective method of keeping us in check. After all, if everything suddenly was legalized, it would (from my understanding) be safe to say that the occurrence of previously illegal acts would sky-rocket, as previously insecure criminals (well, and simply poor people) now would be able to steal anything they find valuable without any legal consequences. So, there we have the good side of punishments; it discourages people from killing, stealing and doing other unpleasant things to each other, and it's pretty safe to say that in the end less people will be hurt.
...But what about the bad side of punishments? Namely the part where the punished individual actually is hurt. I mean, let's say that there was a perfect alternative method of dealing with criminals. This method purely consisted of rehabilitation, and the end result was that the criminal always sincerely felt bad for their crimes. If they were to apologize to the victim or his/her relatives following this treatment, would a punishment really be a necessary act? Would they really deserve to suffer even further beyond their already severe regrets?
As I see it, all who still thinks that a person need to be punished beyond that point do so because of their sadistic nature (which we all have more or less of). After all, the purpose of punishment is to stop people from committing crimes, and since that would already be accomplished, these people would have another reason to support punishments: The pleasure of watching the criminal suffer just like their victims did.
I say that it's inhumane to punish a criminal who is sincerely sorry about its actions; what do you say? Can a person deserve to be punished for its actions no matter how much it regrets them?
Please note that I'm well aware that punishments are currently one of the best and cheapest methods of stopping criminal acts from occurring, and therefore do not oppose them at this point. I only oppose them in an ideal world where the perfect- or highly effective treatment such as the example above is possible.