Why did the German Nazis kill Jews?

Since the Middle Ages, Europe has been very exclusive to Jews. Jews are highly educated, have a lot of social wealth and are immigrants. Of course, it will be rejected by local residents, and so will Indonesia. It is very dangerous for a few immigrants to control the economic lifeline of a country. Jews do not believe in Christianity, but believe in pagans. Most European countries exclude Jews to some extent. However, the massacre of Jews in Germany was completely Hitler's abnormal condition, because Hitler was extremely crazy to commit such acts of genocide. At that time, most Germans often knew nothing about the Jewish Holocaust.