The obsession with "black crime" and "black criminality" is not that of the White Right exclusively. It is a common belief that that transcends the political divide, has existed since the founding of the nation, and is repeatedly circulated and reinforced by the mass media, as well as other agents of mass political socialization and control in the United States.
Experts on the topic have repeatedly demonstrated that the American news media lies about race and crime. For example, black men are over-represented as criminals relative to actual crime statistics; white criminals are shown on the evening news at rates far lower than the actual data would suggest is accurate; white people are much more likely to be shown as victims of crime while people of color are far less likely to be depicted as such. The Americans news media also humanizes white criminals (showing them in business suits, talking about their families and mental health) and dehumanizes black people (showing black suspects doing the "perp walk" or in handcuffs of shackles).
News coverage is not natural, it is shaped by the decisions made by producers and reporters. Thus, a racist society will likely produce racist news coverage because the individuals involved in shaping that final product--and thus public opinion--have internalized said society's values.
The corporate news media reflects the values and priorities of the elite. The news media also help to set the political agenda--and to persuade the mass public into following it. This is the propaganda function of the news.
In the aftermath of the Charleston massacre, the public discourse is being shifted away from talking about white supremacy, anti-black violence, white masculinity, terrorism, and guns towards an exclusive focus on gun control laws in a vacuum that does not deal with the other issues.
[Being sufficiently vague, I was a personal witness to that shifting of the public discourse away from race and towards a race neutral discussion of gun laws last week. The narrative can be changed in 5 minutes folks.]
This morning Meet the Press offered up a master class in shifting the narrative about the Charleston Massacre by defaulting back to the same white supremacist stereotypes about black men and crime that Dylann Roof used to rationalize his cowardly deeds. Thus, a crime of anti-black racial terrorism is transformed by the "liberal media" into a story about guns and gun crime as committed by black people.
Meet the Press was playing some 3D chess with a meta-racism opening. We whose eyes are open can see what is actually happening, what of those who are still asleep?
As goes the saying, if you do not understand white supremacy you cannot understand American life and politics. "Until you understand racism nothing else makes sense."