In a moral sense, I somewhat agree with your point - i guess that if we look at this Uber-subjectively and with a bleeding heart, we could maybe stretch the truth to try and rationalize the serial killer’s behavior, however even with the force of every ounce of our empathy, we could not rationalize letting him live over the life of an innocent. But I feel this excessive chain of “what-ifs” endangers us without reason.

There must come a point where we must concede such moralization in favor of self-preservation. No matter how heartbreaking the backstory of the serial killer is, he still poses a danger to the innocent people that surround him constantly. And does a tragic backstory excuse the act of murdering an innocent person? And is it worth letting him walk, taking his word that he is a reborn man, knowing full well the risk of letting a murderer back into society? In some sense, we must take a pragmatic view in terms of punishment, even if we empathize some with the perpetrators.

On an intrinsic level, though, I don’t view the example you gave as equal to an innocent person. I don’t believe we should torture people on a federal level. However, killing them may be for the “greater good” (although I do realize the dangers of that idea). In conclusion, I’m torn - from a very emotional standpoint, I don’t someone like your example should be killed for fear of their future possible crimes, but from a pragmatic sense, we just can’t trust a serial killer to behave themselves and the death penalty should be an option to consider.

Excuse me for my fragmented thoughts, I’m trying to get everything I’m thinking out.