A scene from “Guests”

There is no logical pathway that would lead you from atheism to do those terrible things. There is a logical pathway that would lead to that from a Christian religion or something like that, or from one of the state religions like Nazism, like Stalinism, and so on. You really can justify doing those awful things if you believe in something as strongly as religious people do. But nobody is going to go and kill for the sake of atheism. Why on Earth would you?