Simply put, this is a seniority issue, meaning it is a grievance issue. When I went driving way back when, our HR manager was AA. He hired five AA drivers with less seniority than me before I went. All I did was wait until I gained my 30 days and filed a grievance. My seniority date was changed ahead of those five guys. Case closed. Do yourself a favor and drop the racism talk. This is a simple black and white issue, and I'm not talking about race. File your grievance as a contract dispute and nothing else. Maybe it is racism. So what? Are you going to file a lawsuit? Then treat it as it is, a contract issue, and go back to work.
When I was a cover driver, I had other cover drivers with less seniority get favored by sups who were friends with them. I had to just stand up and tell them I had more time and I would file on them if it continued. that was all it took. I recommend you do the same.