Inferiority complex, they're so ashamed of their history and would do anything to divorce themselves for that, including taking credit for other people's cultures and religions.
A lot of them minimise to outright deny the transatlantic slave trade even happened.
In a way they reinforce the white supremacists world view that black people are an Inferior bread with no civilisation.
The funny thing is western Africa and the bantu people in general had plenty of great civilisations with plenty of polytheistic religions.
