It's important to be correct about the particular nature of the injustice: the police aren't profiling people who are probably doing something illegal. To the extent that police do profile (I don't think it's a question that they do, only to what extent), their profiling is based on who they perceive to be the most likely of committing the worst offenses, not simply "who is likely to be doing anything illegal at all".

That said, even if black Americans are more likely to commit these worst of offenses (as reported by victims), it's still unjust because any given black individual may not be guilty and doesn't deserve increased scrutiny based on the color of their skin--justice ought to be colorblind and individualistic.

That said, not everything that appears to be profiling is actually profiling. Police are deployed more densely to areas with high violent crime, and these areas tend to skew black. That means they're more likely to witness more minor offenses as well. The racial disparity here isn't due to profiling, its due to the high incidence of violent crime in certain predominately-minority communities. This is an important distinction because it determines the best course of action to solve the disparity problem--if the problem is mostly attributable to police profiling, then fixing profiling is the most urgent problem. If it's due to high incidence of violence in communities, then the best solutions will be various anti-violence programs and keeping violent offenders off of the streets (and ideally rehabilitating them).