I have an idea why you think it matters, I know why I think it doesn’t. If this was a race based killing, that can be taken into account at sentencing.
There’s a pattern of disproportionate use of force against black folks by police in the US. I’m not going to argue with you about that fact. You either know it’s true, or will not be swayed by any evidence I present anyhow. And when police kill someone who may be yet another example of this, it matters and is worth including.