The show only reflects what is happening for the participants and their perceptions of "how things are". That's all it can really be taken for.
I don't think the issue would be the same for the other places you mentioned because, while slavery undoubtedly existed there at some points in their histories, they didn't make big business out of ripping people from their homelands and then, after they were later 'free', openly discriminating against them for so many years and THEN (later) trying to live with them as "equals" when they were clearly not.
It is a very complex issue, and the show only touches on the participants' experience with it. Neither is completely right OR wrong. But it is an interesting social experiment.
Dogs have owners
~ Cats have staff