Marx wrote extensively on slavery and colonialism. The Bolivarians are the ones claiming that he never wrote anything about slavery and colonialism because he was the person who debunked Simon Bolivar, calling him the Napoleon of Latin America. The real slave liberator was not Bolivar or Lincoln, it was Toussaint Louverture known as the Black Jacobin. Haiti did have a real antislavery uprising and it had an enormous influence in all the Americas, he never received the proper recognition because he was a black man
“The American South, despite its slave labour, was basically a commodity society in which goods (including slaves) and services were produced for sale on the market with a view to profit. A more fitting designation for the system is <i>Plantation Capitalism</i>.”