@Chaotic Good-ish Barbarian What makes someone rape a child or an old woman, or kill 1 baby or a million citizens, is something that needs to be understood. There is no predisposition to any behavior. I dare you do find that. It is the environment that makes people behave the way they do. So we need to look at that and change that.
If you execute these bad people, the same conditions will create more of them. It's like you try to prevent climate change by blowing up oil refineries to stop people from burning fossil fuel. But you don't understand that the Trade Society we live in, with its institutions and rich people who control our resources, will be incentivized to drill more for oil because it is profitable.
If you don't know what is the cause of a problem, you cannot find a solution for is.