[gregschlom]

Thanks for the explanation on the individual level. Sounds reasonable.

On your second point, yes, you can say of any cultural group that there are people who do X and people who do non-X, but that doesn't proves that there are no global traits and that all cultural stereotypes exists for no reason.

But I understand your point as "you are wrong to try to attribute the behavior of an individual to a stereotype, since they can only be used at a very broad level", and I think you're probably right.