Thanks for your response. I would say that the links between BLM and Marxism and Marxism and the Soviet Union are the ones I disagree with the most. Although there are Marxists involved in the movement and the Soviet Union identified as Marxist, I don't believe these things necessarily follow. That to me is like saying Christian -> Conservative -> Military Dictatorship -> Pinochet -> death flights.
I agree that someone who wants to implement a government like the Soviet Union is a serious danger to the Republic. My understanding of Marx is that he saw Capitalism as revolutionary and a very positive step away from Feudalism. However, it has some very serious flaws that will inevitably lead to it needing to be restructured so that power is shared more equitably, production is geared towards human needs rather than profit, and people have more freedom in how they associate. I think of it as an extension of (classical) liberalism rather than a rejection of it, although obviously there are people both left and right who would disagree.
I would argue that regardless of what Marx intended, the people I know who identify as Marxist have libertarian leanings which means they intend to take an entirely different direction from Lenin, Mao, etc. As far as BLM, Libertarian Party presidential candidate Jo Jorgenson has been very supportive of the movement as have many other right-wing libertarians. I see BLM as inherently anti-authoritarian with a diverse array of opinions.