I think your stats are quite suspect (in fact, made up, as you pretty much mention) and no, it's not at all irrelevant. I know my family history back to the 1600s; these folks were poor as dirt and indebted at times but they were not enslaved. (Some were part of this European 'crofting' system but that is not the same as slavery.)
More importantly, I can ask around in my family and find out family health history, how long people lived; I know where they came from and can find relatives. My African-American friends cannot all do the same. For some, their known family history only goes back to the last slave sale. They don't know where their ancestors came from in Africa. They have limited knowledge of family health history, compared to what I know. I know the language my great-great-great grandparents spoke; they don't. I can do research on historical foods from my area; they can't. With the advent of modern genetics, some can figure out some of that (look, maybe I'm Igbo, let me go to Wikipedia and look that up....) but it's quite different than being able to ask your aunt to set you up on a tour of where your ancestors lived in the 1700s and her being able to just look on her desk for those files.
Many white people were literal slaves around the same time (in the 1800s and before). Look into the Barbary slave trade. Over 1 million white people were held as slaves in Africa. Even some Americans were held as slaves in the Barbary Coast.
“Sufferings in Africa” is a fascinating memoir of some white sailors shipwrecked and enslaved in Africa. The book inspired many white leaders in the US to empathize with the abolition movement.
More importantly, I can ask around in my family and find out family health history, how long people lived; I know where they came from and can find relatives. My African-American friends cannot all do the same. For some, their known family history only goes back to the last slave sale. They don't know where their ancestors came from in Africa. They have limited knowledge of family health history, compared to what I know. I know the language my great-great-great grandparents spoke; they don't. I can do research on historical foods from my area; they can't. With the advent of modern genetics, some can figure out some of that (look, maybe I'm Igbo, let me go to Wikipedia and look that up....) but it's quite different than being able to ask your aunt to set you up on a tour of where your ancestors lived in the 1700s and her being able to just look on her desk for those files.