Agreed that capitalism is post-slavery. The historian Eric Williams wrote that slavery did not come from racism; racism came from slavery, and I suspect he would agree that racialized slavery was a product of the final stages of mercantilism.

I have read the theory that racism has its roots in antisemitism, and I don’t discount that entirely, but I suspect that’s only one of many roots that came together in the late 17th century to give us racism. Antisemitism takes several forms. Identitarian antisemites insist Jews cannot meaningfully convert and any Jewish blood makes someone a child of the devil. But that model is all about bad religion instead of bad science, so I think it’s not significant in the development of the theory that some races are superior and therefore may exploit the rest.

I also suspect Marx had in mind what wealthy Florida farmer explained around 1960: “We used to own our slaves. Now we rent them.”