Hitler was a very evil guy. He was also very shrewd. He knew that one way to unite the people was to come up with a common enemy. He had his propaganda organization demonize the Jews and the general population tended to unite behind him against the Jews. It was a simple and cruel political maneuver.
His Jewish heritage has never been proven, as far as I know. It was an allegation that his grandfather was Jewish based on name. But he attended church services as a child, according to historians. he later became an atheist, according to Goebbles.