It would be interesting to see if more progress would be made if the protest was framed as "cops harm/shoot/kill too many citizens" rather than "cops harm/shoot/kill too may African-Americans".

No doubt the problem is worse for African-Americans.  But it's a problem for other groups too (particularly men of all races).  If it wasn't framed so much as a racial thing, I think it would attract far more support.  And the benefits would still flow disproportionately to African-Americans.

I think it is an unfortunate commentary that people are unwilling to stand up to anti-black racism.  But from a purely tactical point of view, I think downplaying race would result in more progress on the issue.