(3/?) But the ones that kill make life nasty and then they're tortured in hell. Why create them in the first place? Without them, the non-killers would still have free will.
(2/?) Why does it have to do with robots? Currently, there are two types of people being born: ones that kill other people and ones that don't. They both have free will.
(1/?) Not at all. No good without bad is catchy, but it doesn't mean much. What's the problem with having a planet only with people that don't kill other people?
This is a wicked problem, idk if you've thought it out completely. Do these beings die? Would it be impossible for the others to influence the timing of said death? What about torture?