Ainsley Harriott appeared to know very little about slavery.
I just watched it again and that's not the impression I got.
He'd have to be spectacularly ignorant not to know how and why Black Africans ended up in the Caribbean.
He was extremely angry when faced with a memorial to the man who held his ancestors; was very surprised to find that another ancestor was free-born; and was again angry when it was revealed that his surname comes from a slave owner.
You can be fully aware of all these things (as with the holocaust) but when you're faced with it, face-to-face, in your own ancestry, that's a different thing. On a different scale, I know full well that TB was a major killer in the late 19th century, but it doesn't make it any more comfortable when I find a great-in-whatever- degree uncle or aunt dies of TB/pthisis in infancy. Similarly, I know that in the 20th century, meningitis was a killer, but found myself strangely moved when looking up a death for another rootschatter in one of the county forums - born Q2, died Q4 of the same year - and that was something totally unrelated.