From what my grandma and other North Africans tell me is that while they’re Arabized, they weren’t slaves. North Africa up until the 5th century was Catholic. The Berber Catholics had a huge falling out during the oppression of Christians under Emperor Diocletian, many Christian leaders obeyed the order to surrender sacred texts to state authorities for destruction. One of those who agreed to do this was Felix of Aptunga, which made him a traitor to the faith in the eyes of many. After Christians regained power, some believed that those who obeyed the state rather than become martyrs should not be allowed to hold church offices, and that included Felix. I feel like the amazigh became Muslim because their values align with their values more .