I work in this world and, while I'm not saying it isn't understandable due to the reality of what happens in our world, LEO in general are less likely to give the benefit of the doubt to a black man over a white man.
I have worked in LEO. And there are exceptions, I'm sure. But in general, LEO would give the benefit of the doubt to a black neighborhood watchman in his mid 30's, that has contacted 911, and believes he is protecting his neighborhood, over a white teenager with a criminal record that had doubled back and was beating up the black guy.
That's a fact.