A white man and a black man walk into a fried chicken establishment. One of these men is here to get dinner for his family, and the other man is the butt end of this joke.
Stereotypes are cultural, not logical.
Comment A (original): 'stereotypes have a reason.'
Comment B (me): example of a stereotype without reason, which happens to originate from the US
Comment C (you): 'You're generalizing the US to the entire world.'
Maybe I should have included a warning to ease the shock: 'You're about to read an example from the United States.'