By the numbers alone it won't work. Black Africans are more than 80% of the population in South Africa. Black Americans are less than 12% of the population here. That 12% has a fraction of a percent share of power in our politics. Racist white socialists are just using Black Americans as a tool, per the norm.
True.
But I doubt the left would put that much thought into it, they only see a way towards their totalitarian utopia and modeling it off other hellholes seems to be their thing.
On top of that, legalized abortion combined with the end of “cash for kids” in 1996 slowed the black population growth to near that of whites - now urban areas are ringed with masses of imported Hispanics and Asians that have no common ground with the urban black population (in fact, they demand police protection FROM them).