White supremacists would have you believe it’s proof of some kind of genetic inferiority. I could get into why that argument is utterly retarded but it would be a wall of text so, unless you ask.

Of course it's utterly retarded. Like I said, I would predict it's due to the largest target demo for gang recruitment being young black men. Combine endemic fatherlessness with poor socioeconomic options and you have a demographic that is ripe for recruitment by groups that offer money, male bonding and a kind of sex appeal but also results in being a root cause for a lot of violent crime. It's basically the black version of tradcon alt-lite recruiting - you offer pseudo-paternal figures, a route to money, and a claim to be able to attract women and fatherless, sexless young men with no real purpose will flock. The main difference is that the alt-lite groups for the most part aren't dealing drugs and shooting at each other, their game is marginally more subtle and longer term.

The rate goes from 50% to 40% when the “race: unknown” cases are removed.

How does that work? If a category is some share of the whole, and I remove some number from the whole but not from that category, how can the share go down? Or am I misunderstanding what you are getting at? It's not like UCR numbers count anything with an unknown race perpetrator as having a black perp.

A black person is 7 times more likely than a white person to be wrongly accused of homicide.

I'd be curious of this: Out of cases where a person is wrongly accused of homicide and arrested, how often is the correct person later identified and more importantly, how frequently is the correctly identified person a different race than the wrongfully arrested one? Because (ignoring the injustice of wrongful arrest for a moment), arresting the wrong person for a crime done by a person of the same race isn't going to have an impact on your racial breakdown of perpetrators.