Eugenics was a popular theory of the time. Many people believed that certain "types" of people, including blacks, Jews, gypsies and homosexuals, were inferior. Many Germans, being efficient at accomplishing whatever goal they were seeking, decided that Jews, blacks, gypsies, homosexuals and political dissidents should be exterminated. The German war machine needed money, why not confiscate the personal property of those people to fund their war. It was more of a 100% tax than true hate. But to make it work, the German government needed to work up a little contempt and did so by claiming that the germanic people were superior to everyone else and should be ruling the world.