Thanks for this. This is really important. I have prejudices. And I can guarantee that you have prejudices. All people are subjects of the racial attitudes they've been taught, the stereotypes in our media, and sometimes from our experiences.
We have prejudices, but in my opinion, that doesn't necessarily make us racist. Suppose that cop in your example held his prejudices, but never took any actions as you describe, and never expressed his feelings publicly. In my personal dictionary that makes him prejudiced, but not racist. To me, when personal prejudices are turned into offensive actions - which includes words, as they can cause damage as well - it becomes racism. When the prejudiced cop pulled you over because you are Black, that is a racist action, and once he does that, he becomes a racist.
I have my prejudices. I remember a few times walking down the street late at night and several Black men were approaching from the other direction, I felt anxiety. That is because of prejudice. If I crossed the street because of it, that would be racist. What I do is puff up and look confident and tough, but I try not to be racist.
According to Marley K, I am a racist, because my skin color is pink. I really think you have identified a really important point that we need to address if we will ever make progress on this issue.