But it wasn't the soldiers who started the war, was it? It almost never is. Soldiers are trained to follow orders, and orders that would make most sane people sick to their stomachs. Killing another man is not an easy thing. So armies try tricks to make it seem more palpable. Sometimes they spread rumors that the other army isn't made of humans at all, that the people they face are not truly people, and so it isn't such an awful thing to kill them.