Every being in the universe knows right from wrong.
Let me tell you something. You humans, most of you, subscribe to this policy of an eye for an eye, a life for a life, which is known throughout the universe for its... stupidity.
Unfortunately, this is nonsense. Most beings that we know of (life on Earth), ruthlessly do whatever is necessary for their own survival. "Right and wrong" or "fairness" is a human invention. Social animals (including humans) have developed a method of dealing with other group members that looks like fairness - but it is merely a way to improve chances of survival. If you hog all the food and your group members starve, there is no one left alive to help you get more food. It is well known that this "fairness" disappears in situations where personal (or offspring) survival is at stake.
It is a tragedy, but overall, life has absolutely nothing to do with fairness. Just about every life form is killing and consuming other life forms. If there is a God monitoring day to day activities, he certainly doesn't care about fairness or justice. Otherwise, how can innocent grazing sheep be butchered and served up for dinner for a CEO of a huge corporation that is polluting and raping the planet for profit?
I don't see it as 'acceptable, providing we attach x,y and z conditions', I see it as wrong. Full stop.
Torture is a horrible evil thing. If this horrible evil thing is done to someone you care about, I don't see how you can ever get over it until you get at least a bit of "anger releasing justice".
Imagine you have a beautiful 5-year-old daughter who was kidnapped, brutally raped for weeks, tortured with cigarette burns, beaten with a pipe, then left for dead in the woods. She lives, but with permanent physical and psychological damage. She will never be the same again. She survived, so the villain is not charged with murder and only gets 12 years in prision. With good behaviour, he can get out in 6-8 years.
Imagine you see the {bleep} in 7 years and he's smiling and laughing at you. He "served his time" so he's free. Meanwhile, your whole family is permanently damaged. How could you live with yourself? Wouldn't you feel more "closure" if you could have caught the {bleep} before the police did and spent a few weeks damaging him? At the least, you need to have done something that permanently reminds him why he shouldn't have done it. (maybe cutting off his genitals and feeding them to your dog?)