I have no idea if that is true or not, but it is irrelevant because it is quite possible for black people to be racist and also to take part in anti-black racism.
The proud boys leaders name is Enrique Tario, he's afro-hispanic I believe. Regardless, the proud boys appear to be a multiracial group of Western chauvinists, believing that Western ideas and culture are superior. Progressives seem to believe that Western = white, and that is how they make the leap to white supremacy in this context. Whether Western is about ideas vs skin color isn't a debate I'm interested in, just wanted to provide context.
> Progressives seem to believe that Western = white, and that is how they make the leap to white supremacy in this context.
I'll note that my comment did not directly link proud boys to "white supremacy". Instead, I (and the comment I replied to) used "right-wing extremists". I think that's an accurate description that does not require an assumption that "Western = white".