African-American slave auctions were a pervasive part of American history, something that was upheld by the U.S. Constitution and the general American public at the time. It was a vital part of American economy and culture, and millions of Americans were auctioned off in this way. Our history of slavery and its legacy is a national disgrace, and American society is still dealing with its negative aftereffects to this very day. It will probably always affect us in some way. For that reason, we can never make light of it in any way.
The wench auction scene by pirates in the ride is something that might have happened on occasion, but it was never a widespread practice or upheld as part of the culture. (And please don't counter that women had fewer rights & were sometimes abused. Of course that is true, but I'm referring to the actual events we see in the pirate auction scene.) Yes, African-American women were sold and raped, but that experience was part of the slavery experience, & one of the reasons why an African-American slave auction would never be part of a ride. It would be too realistic.