Concerning police and justice: Nothing wrong with having their own, as far as they live inside their own state. Which is actually the answer to the rest as well. Why only segregate history and not math and science as well? And what about reparations to those who are descendants of whites sold as slaves by negroes?

If you want racial justice, you should have your own state where your successes and failures will be your own responsibility.

Now nothing of that would have happened if negroes were given their own state back then when the American Civil War was fought.