Because time itself is not on your side here. We can control for racism, and see it isn’t the primary factor anymore.
Thomas Sowell is a black man who grew up in 1930s Harlem, yet he would argue that Harlem is worse today than it was then, especially when it comes to graduation rates of high schoolers, rates of African Americans climbing out of poverty, and their ability to build themselves into nuclear families.
You can’t blame racism for those things getting worse, because clearly we were more racist 80 years ago, than today. So something else is the driver for why those things fell.
Roughly as many unarmed black men are killed per year by cops as they are by lightening strikes each year.
You’re falling for the spotlight fallacy; individual incidents grab your attention, and that makes you think that they’re more common than they are.
Now, that doesn’t mean cops aren’t doing cruel or incompetent things, they are, and that Police Departments don’t protect bad officers, they do.
Policed Departments are insulated from adjusting bad practices, and protecting bad personnel, for the same reason you see Schools do it. They’re a state-run monopoly, captured by a Union, that itself has a captive membership.
And in these situations, it’s the poor who suffer most. In these large urban environments, thanks to a mixture of migration patterns, and decades of bad policies, the poor is disproportionately black and hispanic.