Oy.
First, not even LIBERAL academics believe the black-power business about Egypt being black. It wasn't. Blacks were never more than several hundred miles to the south, in Nubia. The Egyptians of history were probably Semitic-looking people, much removed from black Africans. In fact, one pharaoh decreed that no blacks were allowed in Egypt, except as slaves.
Two, let's assume, for the sake of argument, that all your information about great African cultures is correct. Do you seriously believe that the only explanation for its disappearance is colonialism? That's fantastic, especially when you have other colonized areas to compare it too. In other words, if blacks are so great at nation-building, why don't they get off their asses and build one? Africa's loaded with natural resources, and the whites are either being killed off or forced to leave, as in Zimbabwe and South Africa. What in the hell is stopping black Africa from blossoming into space-racing, car-building, clean-water piping, Starbucks-sipping, French lit-reading societies? And please don't give me the "it's their leadership" crap. There are leadership failures to go around, but a race that can't figure out agricultural techniques mastered by other groups hundreds of years ago and ***** infants as a cure for AIDS isn't suffering from mere "leadership" problems, man. They're stone-age people, biologically and mentally, and you can't bring 'em up to speed by air-dropping MacBooks.