I learned about Marxism from the source, reading Marx.
Calling BLM an organization is like calling peace or women's rights an organization. It's a cause that includes organizations and unaffiliated people.
Notice how Birx keeps changing his tune? Whitesplained how bad it was for a mostly Black team to support Black Lives Matter, which they are too dumb to know. Then Black Lives Matter is bad for race relations, which were so much better when black people didn't protest. Then it was 17 people killed by BLM, none of whom he could name. Then BLM is racist because I don't know, criticized racists? Now BLM is Marxist. Based on the everchanging right wing web site he is citing.