In 19th century academic painting voluptuous nudes were so endemic that it was necessary to find good excuses for their omnipresence. So they were situated in mythological, biblical and not at least historical sceneries.
One of the most popular practices to place nudes in history paintings was slavery. Paining nudes on an antique slave market was not only a good excuse but also kind of politically correct. Superficially accusing the suppression and exploitation of the poor females the artists could paint gorgeous nudes and exploit them themselves by selling them in the art market.



In the long run nearly all these paintings are cheap exploitation already long before the word was used in that context. I know only one painting which offers another point of view on that subject: A Slave for Sale (c. 1897) by the Spanish painter Aranda, José Jiménez (1837-1903).

Really a great piece of art!