I frequently address the idea that the root of racism is low expectations of a racial group. Expectation often set by stereotypes built upon observation of a subset of the group.
Is anyone surprised by riots, looting and violent assaults on white people after an injustice to a black person is nationally publicized? Does this make us racists? It is certainly a low expectation, but it is of a subset of a group and does not indicate that it is a characteristic of the entire group (the "not all" that is so often ridiculed on Medium). I would be surprised and disappointed to learn that any of "my friends" who are black did such a thing, yet the universal lack of surprise persists.
Expanding the idea, should absurdities like this make me think that all PhDs and professors are idiots? Perhaps if she studied math she would know subset theory. https://www.nationalreview.com/2017/10/math-racist-university-illinois-professor/
My point is that racist low expectations are often thought to be reasonable based upon stereotypes formed from confirmation bias supporting observation of the low order subset of groups. We see it in matters beyond race; police, salesmen, gun owners, the people on the other side of the political isle, writers of dear white people articles, etc. It would go a long way if people quit drawing their circles so large.
The line between lack of surprise in a negative view of a group and people we know being seen positively is blurred, as if we are somehow blessed to know the exceptional good people in the group. Perhaps we are blessed to not know the jerk exceptions personally.