Actually, a whole bunch of Muslims captured and enslaved blacks and sold them to the whole world. And now a bunch of black people are angry and at Christians (it was Christianity that inspired the emancipation movement) and became Muslims, unknowingly taking on the religion of their slavers. Who are still enslaving people nowadays too!
Interesting measure of the relatively good treatment of blacks by Christians versus Muslims - far more blacks were sold into Islamic slavery than sent to the Americas. And there are almost no signs of black ancestry in the Middle East despite a thousand years of Egyptian Copts, Sudanese and other African slaves sold to Muslims while there are large black communities throughout the Americas.
There were writers in the 1800s who talked about how all the blacks died after a few years and had to be replaced, almost no children born much less lived. In contrast, those in the Americas were able to live and have families - to the point that they have discernible descendants.