Well you can say Hitler's hatred for the Jews was in political in a way too. He didn't just hate Jews, he hated all religious groups. He felt that Christians were more of a threat and was planning on targeting them after. He pretty much targeted anyone that threatened the Third Reich(ie. SA and Rohm) just like Stalin did.

Stalin killed about 20 million, Hitler killed about 12 million. So I think Stalin was much worse since he killed his own people and even a large number of his own generals.