Not only that, you also need to brainwash them to think their enemies as non-humans. It is much easier to kill an animal than to kill a human. That is where Nazism and terrorism are close to each other. For Nazis, the racial purity and superiority are paramount. To think your own race to be supreme, you need to think everyone else, particularly your enemy, is below you. For terrorism, using Islamic terrorism as an example, you must think your enemy not fellow muslims. They are infidels and brutes. Nazism is like state terrorism.