The issue boils down to the messaging of god forbid we treat certain people based on race with respect getting bogged down with certain inclinations of people who started the idea, without any sort of mass BLM underground network, just like "antifa"
It's a pure scare tactic, and one that if you ask the myriad of people who live around me with black hearts, and BLM signs in their yards that "DID YOU KNOW YOU ARE ACTUALLY SUPPORTING MARXISTS!?" while sitting in their PV and Leawood mansions, it's a chuckle at the ridiculousness of what is trying to be done. It's all there to once again subjugate the god forbid treating certain people based on race with respect tenement what people really want out of this. It becomes muddled because racists and grifters made it muddled.
It's racist at worst, and dishonest at best trying to shout it down. Ask yourself honestly, if the idea of "black lives matter" came divorced of any origin stories, hell let's say a WASPy ass person started, would it change how you feel about the true message it's trying to say? If it doesn't, there you go.