Why did Hitler want to kill Jews?

What Hitler talked about was the idea that Jews were a kind of subhuman who could only destroy civilizations.  He believed in a three-part categorization of human beings.  Aryans, at the top, were the only ones able to create civilizations.  They were called "culture-creating" people.  The next category was "culture-bearing" people like Latins and some Asians -- they could maintain a culture once it was created but could not make their own.  Finally, there were "culture-destroying" people like blacks and Jews.  They would destroy cultures out of incompetence and malice and greed.

Hitler believed that Germany had become infested with too many Jews and that was why it was no longer able to hold its "rightful" dominant place in the world.  This is why he wanted to get rid of Jews.