The aims of the protests are to shine a spotlight on police brutality and qualified immunity / defund the police / ensure that killer cops are prosecuted / damage property in pursuit of anarchy / score a new TV / whatever. It's all fairly clear and makes enough sense.
Your idea, however, leaves us with nothing but a knowing look and an appeal to not trust the narrative. If you can read any broader frustration here, it's because all the "but what about white folks?" people in my social circle have been following the same playbook.
So where does it go? Does your argument conclude that the police should be harsher still towards black people? Does it suggest that police who kill should suffer less scrutiny than they presently do? Is the status quo fine, and the resolution should be that everyone just shut up and go home?
What's your call to action here, and what would be the immediate real-world consequences of your worldview?
If they had said that the protests were fine but next time we expect a shout-out, then the discussion could move on. Much like in this example.
So you want to dilute the protest which is specifically about police violence against black people into something entirely different? You're essentially arguing to destroy the entire protest for something it's not at all about.
Protesting police brutality against black people is protesting police brutality in general.
The "general narrative" is about rampant police brutality that first and foremost disproportionately affects people of color. It's a problem that's existed since the inception of a police force in the US and that's what this movement is about. No one is trying to play a silly number game of which race kills more of what other race.