When I hinted about sacrifice, I was too avaricious of details.
To us, evildoers are people who fail to realize that violence is rarely fitting, and use it in a brutish and evil way.
Yet, to us, nobody "deserves" punishment. Punishment is inherently useless. An evil man could be forced to witness his crimes and, exactly as you said, facing rehab, modify ons'e standard and realize we have been bad persons, is worst than any torture. Becoming good, for a former bad man, is both salvation and punishment, as it both purifies you, and also open your eyes about how bad have you been.
No, we don't punish, that is not our attitude. We rehab. There are countless ways to do that to convicted criminals. You have been too pessimistic in believing it's impossible to make those feelings surface in a bad man. Nowadays, almost all of them undertake psychological therapy while behind bars, to become better persons. Sometimes, even simply the passing of time forces a brute to reflect his own past. We never condemn on a moral standard. Unless that person is Beyond salvation, in that case, to us, is not even a human being anymore, just an enemy of the human race, and enemies are to be rooted out. But also in this case, jail is more than enough.
But sometimes, some people, in some situations of the world, simply cannot be jailed. There are places, in the world, where wars are going on, and jails are controlled by those very gangs that should be trapped inside so to avoid disturb people again.
In these cases, death becomes not "fitting", as I said in the beginning we don't believe in punishment at all, it becomes necessary. And here Witchcraft adds its own to this absolutely "non-occult" truth (for "truth" here I mean that some criminals simply won't surrender)
The Gods feed on life-force, and usually extract it from evil spirits without bothering humans, no matter how evil: but in the rare case a human is so bad that he would never ever repent of his actions, to the point that putting him under arrest would mean nothing and fail to prevent him from being back to a life of crimes (like some terrifying mob leaders in South America, that killed and tortured thousands of persons), in that precise case that man must die, and since he will die, why failing to realize that his life-force can be offered to the Gods through a ritualistic execution? Not as a punishment. That man simply "had to" die, then why don't give all his electromagnetic energy to entities that will use it to shape the Collective Unconscious toward a better future?
I know that for centuries the Church had been scarying people about the fact that only evil spirits accept blood sacrifices, but this simply isn't true. I have known the forces of evil and believe me, they are unmistakable. Gods are different. They just understand that violence is a universal law, and teach us how to avoid the violence we all know, that of hatred and intolerance. As I wrote in the previous post, that is the evil violence we all condemn.
In a world without evil doers, offerings to the Gods will be done by animals only (Always in order to be cooked and eaten, and as painless as possible, never as animal cruelty), and by human sexuality. They don't ask for human sacrifices: They are just wise enough to understand that some humans have to be killed, and thus just accept their lifeforce as a gift.
I have wrote an extensive post before this one, don't be scared into focusing only on the portion that troubled you We even lie about all of this, talking only about peace, not as hypocrisy, but because we believe in peace so much, than when we feel the one in front of us could misunderstand and misuse our philosophy, we prevent him from feeling somehow authorized to thrive in his own aggressiveness, and thus we speak of peace only. We are not bloodthirsty. We just want to know how violence works, and when it's fitting to use it.