3 words. Black lives matter. This should be about reaching out to the black community to show that racism towards black people from white people is not tolerable.
I'd happily continue the theme and say Gay lives matter, reaching out to the gay community to show that abuse towards gay people is unacceptable. I'm saying this as a straight, white male.
You seem to think this creates sects.
You obviously prefer a vacuous, rhetorical statement which does piss all to acknowledge the abuse dished out to others. If I racially abused someone and went back to apologies and said all lives matter, I'd get punched.