Who's ignoring history? Lots of things change through time, the roles played. Cops don't kill blacks all the time. Things have improved alot. More than you obviously want to give credit to. You can cry about 'slavery' all you want.
You want cops to get better, defunding it isn't going to help. You want to send social workers to violent domestic disputes? What will you say when they start to get shot or prove totally ineffective.
Just as easy as that, huh? More black people are proportionially involved in violent crime, so that plays a huge role. More whites are still killed overall. When a group representing 13% of the population commits 53% of the murders, and overrepresentated in every violent crime cat., that vast overrepresentation will result in more encounters with police.
That's wonderful, but you have to be realistic. Just watch what's going to happen in Seattle now unless they reverse their course.