Killing at a distance. How about people watching a person on death row have their sentence carried out? Lotta cold ass people in the world. Not all of those people have a mental disorder and can still not feel a thing even if they had to first hand “throw the switch” so to speak.
Parents of murdered kids is a good example. Years in court over something terrible that happens. You could still witness a parent kill the criminal in a heart beat without flinching.
No I am not a murderer. But when you work around lawyers enough. You see a lot of people who have no mental illness and would have zero problems killing. I’ve also had fair amount of folks around me in the military. Plus my uncle was a police chief. Lotta stories there too.
edit:
Short version. You are trying to work out things in your head. That is fine. The point I am making is that the moral compass you WANT to apply to others is not always so easy or cut and dry. Some people just don’t give a damn and don’t have a mental disorder. That is not something you can debate. Peace.