I don't think it's a cover-up. I think there's a lack of emphasis on racism as a motive when it's a black shooter compared to a white shooter. I think it's easier for the status quo to be angry about white-on-black violence because it is perceived as inherently more "racist" than black-on-white violence.

This is due to the fact that African Americans have been the predominant victims of racism in American culture. We have created this conditioned internalized hierarchy of discrimination. The media uses this hierarchy to frame their own narrative.