As a whitesican I can't really comment as to my own personal experience, since I am not black.
But I do think black men have preconceptions about black cops that may affect their idea about how they are/were treated. I'm sure most black men who have dealt with the system have far worse stories about the way they were treated by white cops.
In my experience cops are just like any other group of people - they run the spectrum from good to bad, asshole to chill, etc.