Generalization is important. It helps us manage complexity.

When making generalizations, or stereotyping, it is definitely a good thing to talk about the median person.

For instance, Bernie Sanders gets a lot of his appeal by appealing to the generalized, stereotyped american public. Its an incredibly important skill to be able to make those generalizations in order to get appeal. When talking about "Wall Street" his message is not "this is a multifaceted topic". Instead Wall Street is stereotyped to simplify his arguments.