I'm not disputing any of that. I'm just not necessarily convinced that the mapping of light and dark to good and evil was connected to skin color.
And the 'black magic' traditions of the middle ages almost certainly drew their inspiration from the rituals of the Hellenistic mystery cults and related groups rather than any African tradition or cultures.
All the being said, I'm straying quite far out of my area of expertise here, so I'm certainly open to be proven wrong.