It's a way for someone to seize power over others. It pushes someone else on the defensive while making their own position unassailable.
We had a problem with this where I used to work. One of the employees, a pretty smart guy, would whisper in the ear of other employees things like, "that guy gets away with it because he's white." One of the people he got riled up blurted this out in front of everyone, which got corporate involved.
The problem? The guy making the complaint was one of the worst employees. Both he AND the white guy he was talking about were on the "aren't performing adequately" list, with management just waiting for a reason to fire them both. There was no reason to bring race into the picture. As someone who worked harder and performed a lot better than him, it pissed me off that he was using racism as an excuse when it was really just him not being very good at his job.
