The reason for the #BlackLivesMatter chant/slogan/movement is never more obvious than in a case like that of Ralph Yarl, a teenager who just knocked on the wrong door and was shot twice (he survived)...and the police have released the individual who shot him pending investigation.
When a Black kid can't knock on a door without fear of being shot, even killed, then we need to be able to say *BLACK* lives matter, because it's Black lives on the line daily for no goddamn reason.