Wicked deeds are generally done, even with impunity, for the mere desire of occupation.
No obligation to justice does force a man to be cruel, or to use the sharpest sentence.
The public have more interest in the punishment of an injury than he who receives it.
Any punishment that does not correct, that can merely rouse rebellion in whoever has to endure it, is a piece of gratuitous infamy which makes those who impose it more guilty in the eyes of humanity, good sense and reason, nay a hundred times more guilty than the victim on whom the punishment is inflicted.
Whatever you think of de Sade, he was a complex figure and we should not look for easy answers with him. He was, strangely perhaps, against the death penalty, and he was never put in prison for murders or anything like that.