"No one organization can address all of society's evils and shortcomings."  

True.  But when blacks are murdered far more often by black civilians than by police, AND the organization that calls itself "Black Lives Matter" is virtually silent on the subject of black-on-black murder, I have to doubt the genuineness of the organization.  Reason would tell you that you'd hear BLM address this issue far more vocally and far more often --- if their main concern really were that black lives are being lost to murder.