Police can be scary, regardless if their skin color matches yours or not. They have near absolute authority to do nearly anything, and you'll lose in a he said-he said court case. But good officers can also be a substantial positive impact on society.
Whilst police is scary in general, it is much more likely for me to have an issue with them than someone who is a middle aged white guy, dressed well etc. People tend to judge others based off of stereotypes, i.e. "which box does this one fit in", and I know that the options for me, on average, are not super lovely.
As such, this isn't an argument for or against police or officers. It is something that highlights the "abusable authority" and for some minorities how the police is more "willing" to do so, on average. Hell, we are at the point where standup comedians are joking as "police wouldn't shoot me, I am not black" since it is quite a widespread fact by now.
As a minority, the police is scary. It only takes one bad apple for my life to take a turn for the worse. As it turns out, there is a non-negligible percentage of the population that hates my guts because of colour, so might as well be safe.