The Arab slave trade wasn't based in bigotry exactly but it was justified by a discriminatory attitude toward non Muslims. Islamic law allows the enslavement of non Muslim, and therefore most slaves were taken from Africa and Europe. Over time a racism did develop to further justify it, particularly towards the Africans. It sounds similar to European sentiments on the issue. An Egyptian historian named Al-Abshibi wrote:

It is said that when the [black] slave is sated, he fornicates, when he is hungry, he steals.

And there are numerous examples of people justifying the slavery in that racial way as well as the previously accepted religious thought.

Alexander, J. (2001). "Islam, Archaeology and Slavery in Africa".

Ehud R. Toledano (1998), Slavery and abolition in the Ottoman Middle East

Lewis, Bernard (1990). Race and Slavery in the Middle East.