Slavery started in America after an early attempt at labor organization in Jamestown. In response to striking white workers, they began importing slaves from Africa.
That’s liberal historical revisionism that proposes that the British Empire, which continued it’s historical support for slavery well after the American Revolution, such as materially supporting the Confederate slavers in their rebellion against the U.S, was somehow more progressive in its economic and political system.
Gerald Horne is a right-revisionist anti-marxist who cherry picks and selectively quotes his sources to present his case for historical revisionism. That is to say he does not look at sources and writes his historical thesis to fit the sources, he writes his historical thesis and then makes the sources fit it.
I know it because I own the book and read it and looked at the sources he drew from. To save us both time, I’ll recommend this article from some silly Trot that did came to the same conclusion