And if it's the case that people in the city's black community are committing arrestable offenses (however stupid some definitions of what is an offense for which you can be arrested and charged with for are), then what should the department do? Not arrest people for doing things it's been ordered to arrest people for doing just because it's bad PR?
It's apparently not popular to mention and undoubtedly there are many social victimization factors at work contributing to it, but young men in the black community really do commit more violent crime and crime of many other types than do many young men in a number of other ethnic communities.