I agree. People tend to ascribe inherent traits to other groups, when in fact observed behaviors can usually be traced not to inherent dispositions, but to specific environmental conditions that incentivize said behaviors.

For instance, a white man in our current social environment who exhibits a confident, assertive attitude is well situated to succeed. White men are expected to be competent and often rewarded for appearing competent, so they sometimes attempt to exaggerate their competence in order to meet the perceived expectations.