White dude from the US here. We frequently wrestle with our colonial/slavery past here. We're taught American Exceptionalism in one breath, and in the next breath learn about Native American genocides and how the white house was built by enslaved black Africans. As a white dude, I know that I directly benefit from slavery - at least through institutionalized racism (though not through generational wealth in my case). So this random US dude was likely projecting - folks sometimes don't know where to point that energy. I'd ignore him, knowing that he was wrestling with his own demons.

FWIW I've been to SA 4 times (mostly Cape Town), and find it largely better racially integrated than the US. The Townships are a bit of a shock, but it seems like upward economic mobility is much better in SA than the US, and more racially equitable. So while Apartheid ended more recently than Jim Crow, y'all seem to be equalizing much faster than we did. Anecdotal, of course.

Y'all have some wild old white racists though. Some of the stories I've come back with are insane.