Simply replying "nuh-uh!" to a concept is not much of a refutation

Absolutely is when the concept is a kafkatrap. If accept that "disproportionately affects blacks" is valid then you put yourself in a no-win situation. Either you agree with the next thing which is usually some commie agenda pushing, or you are morally invalidated through "racism". The real explanation of why anything "disproportionately affects blacks" is outside of the overton window so you have to dance around it and can never really make an argument.

Why mention race it at all?

In Biden's America, Democrat run cities have become unlivable due to out-of-control crime.

That is a perfectly reasonable normieboomer take but it goes harder for those who are with it and know that crime is a synonym for blacks.