I agree with you....stereotypes are the basis of racism, xenophobia and anti-semitism.

For example in racism can be created in many stereotypes, one old one at least famous in Brazil is that "black people stink" or "black people are robbers". Said stereotypes without any real basis, all stereotypes are formed in unreal concepts and wrong logic.
"Immigrants are stealing jobs" , " Jews want to conquer the world," and so on.