This is a representation of something that happened two or three days ago.
A group of white protesters (in the BLM group) wanted to represent the side of BLM that isn't violent and doesn't kill and destroy building+national monuments. They wanted to say: "We are not angry and violent. We believe that there should be no racism against blacks."
A couple of black people, supposedly in the head of the BLM group said that these white protesters cannot protest any more. They said literally and figuratively that: "You are too white."
The irony of it all is that these white protesters were protesting racism, while these black people that the protesters were rooting for used a racist ideology against them. They figuratively said (the black people((through their actions))): "Hey I hate racism, there should be no racism. But, on the other hand, you are too white to represent black. "