Why do you think that stereotypes are so widely known by so many in our society?

Everybody knows stereotypes; Asians are good at math, Puerto Ricans are Loud people etc, etc.
But the main reason that it is so widely known is because about 98% of the time it would be true.
Stereotypes also go by gender differences like: Men are pigs, and Women are only good for the kitchen.
Not every stereotype is true though. But they do have some sort of way that it is true. I basically think that people know them since they are mostly found true.