Exactly, and they did it for centuries, systematically because they considered white people trash. So there you have it, white people experienced same shit every other race did
Secondly this is biased. "In the mid-19th century, the term 'white slavery' was used to describe the Christian slaves that were sold into the Barbary slave trade" SOURCE.
Meaning that this slavery was not done because people were white, but most likely done because they were christian.
Third: Take a second look, really, to this page. https://en.wikipedia.org/wiki/Racialization