FWIW, the South Africans I know
(a) are not of one race – there are multiple races represented in South Africa, just like everywhere else; and
(b) take great care to explain that the variant was first identified in South Africa because they had the technology to isolate it, but the variant is known as B1351.
So, maybe the people who are labeled – whether maliciously or not – don’t like it, and that other people think they shouldn’t mind is not relevant.

Charges of Marxism are being made from the alt-right as a way of discrediting them, i.e. doing to them exactly what BLM says is happening.</blockquote.

It's the same shtick you found in the old John Birch Society:
Denouncing everyone else as "COMMUNISTS! COMMUNISTS! COMMUNISTS! THEY'RE HERE! THEY'RE THERE! THEY'RE EVERYWHERE! THE COMMUNISTS! THE COMMUNISTS! THE COMMUNISTS!"

Again you misrepresent BLM. While certainly there are likely some members who believe racial injustice is “the fault of every white person in America” that is not the official stance of the entire movement.

what they argue is that the entire system is racist, in some cases intentionally (ex. laws that target minorities). in other cases it is just a by-product of the fact that whites are in the majority and a mix of other reasons as well.

That a founder has Marxist ideas does not mean the organization is Marxist. They could be vegan as well but it still doesn’t necessarily make the organization so. As Americans we have to own a huge piece of the blame for institutional racism in this country, the same way we collectively take pride in some of the good things we represent. Until we do that, we can’t fix it. There is nothing new about this concept, therefore denying it could be construed negatively, yes.

That a founder has Marxist ideas does not mean the organization is Marxist. They could be vegan as well but it still doesn’t necessarily make the organization so. As Americans we have to own a huge piece of the blame for institutional racism in this country, the same way we collectively take pride in some of the good things we represent. Until we do that, we can’t fix it. There is nothing new about this concept, therefore denying it could be construed negatively, yes.