I have a lot of thoughts on this it seems, and this isn't really a direct reply to you [MENTION=14857]labyrinthine[/MENTION], because it's going to be super tangential, but I hear you and agree with the points you're making, and recognize that comprehension and understanding of harm caused on a very deep level is necessary for redemption.
Part of what bothers me about this thread in general, as well as people in comment sections of articles about crimes calling for the rape, torture, and death of criminals, is that I do not believe they are calling for those things from the moral awareness and understanding that you have. I don't think that they are interested in using those things as a potential means of redemptive transformation through firsthand understanding of suffering caused. They are calling for those things because they believe those people deserve them, and while it may seem like their concept of deserve is the same as your concept of deserve, it isn't, because it's not "deserve" for a higher moral purpose. It is just pure revenge, and there is a difference.
If people want to judge who is and isn't a psychopath through a checklist of traits only, then here is the irony: the people calling for torture of criminals for the purpose of revenge alone fit the psychopathic traits. A desire for revenge. Low levels of empathy. A reductive view of morality. An inability to consider the greater good and wider consequences of their actions. Bloodthirstiness. Hatred. Their psychopathy is just on the side of the law, which actually makes it more dangerous than psychopathy which isn't.
This is because the law and the people who uphold and make laws have power over criminal psychopaths. No one has power over psychopathic application of law. Psychopathic application of law can't be checked or stopped - there isn't really a system in place for that. Obviously a psychopathic criminal who hasn't been caught or imprisoned is just as dangerous, but once they have been, they're vulnerable. Not in the sense of being emotionally vulnerable or whatever, but in the sense that they are vulnerable to the law and under the power of others completely. Taking away someone's power completely and then using that power to act psychopathicly against that population, with psychopathic motives, is wrong. Period.
I think that a lot of people view the law as the end all and be all of morality, but the law is only as moral, right, and true as the people who make it and uphold it. It's a human construct with human flaws. If the application of the law is psychopathic, then we have a huge problem, because it means that we are sanctioning harm that exists for no greater purpose. In order for harm to have a higher purpose, it has to be done with the intent to do good. Punishment for punishment's sake is not an intent to do good.
What is doing good? What is harm for a higher purpose? I agree that it can be having someone experience what they themselves did to another, but there is only a point in doing that if that experience is likely to result in understanding and comprehension. If it likely wouldn't lead to that because the criminal is incapable of comprehending their actions, or if they're already so broken that it would just seem, from their viewpoint, to needlessly victimize them more and therefore make them feel even more justified in doing harm unto others, it's just torture, and it would be better off to just give the criminal a death sentence. (There are more than just these two options though. I do believe that some psychopathic criminals are able to comprehend their actions fully on an emotional level without experiencing them themselves firsthand.)
I have no experience with prison, but I have experienced some degree of "corrective institutionalization," and while it could be argued that of course it didn't work for me because I didn't deserve it, I think that the focus on deserve is pointless. I was viewed as deserving it, which is why it happened, and instead of trying to split hairs and figure out some foolproof objective measure of figuring out who deserves what kind of punishment, which would be impossible because that is entirely subjective, we should try and align our motives and actions instead with what will do the most good, because while still being incredibly complex morally, that is more objective. Punishment can do good, but only punishment given with the intent to do good can do good.
I think that "deserve" should be applied to the victims of crime only, because giving the victim what they deserve, which is as much reparation and healing as possible, is a type of deserve that aligns with the greater good. So say for example that a psychopath stabs someone in the kidney intentionally. The victim lives but needs a kidney transplant, and the psychopath is a match. Should the psychopath have to give the victim their kidney? Yes, because the victim deserves a kidney. Maybe the victim also wants the psychopath to, I don't know, be waterboarded or raped or something. Does the victim deserve to have the person who stabbed them be waterboarded or raped? I would say no. The victim deserves not to live in fear of being attacked again, so the psychopath should be imprisoned. But the victim is not entitled to active retribution. Just safety, health, healing, etc. The reason we imprison people is to keep other people safe, first and foremost.
I do support the death penalty for people who have committed horrific acts and cannot be reached or redeemed, or if the act of trying to redeem them would be so difficult as to be virtually impossible - in other words, if a large amount of resources would have to be spent trying to do something that would never result in some sort of payback for those resources. So if the effort put in didn't at least equal the finished product.
Wanting punishment for the sake of revenge alone is wrong, and is a perversion of justice. Not because I think criminals should be coddled, but because without a motive for greater good, it will obviously not do any good for anyone. I think satisfaction gleaned from the pain of others in this context is sometimes mistaken for greater good, but it's not, it's just sadism. Punishment, justice, law, cannot be psychopathic. For the good of society and every individual in society, it can't be, and it is so so important to be aware of that actively, because psychopathy sanctioned by law is the most dangerous and destructive kind.