And James II formed the Royal African Company to sell slaves to the colonies. Of course Charles can disclaim that ancestry since his ancestors were in various German states at the time
Actually James I granted the first charter, but to trade more than just slaves.
Charles III isn’t descended from James II but he is descended from James I (through James’ daughter). The legitimate lines of descent from James II died out in the early 1800s. Possibly there are descendants from illegitimate children if he had any (he did have mistresses) but they don’t count as far as claims to the throne.