Ask yourself why they are so outraged that he's not portrayed as black. You've really got to have a low self-image in order to think that you are somehow helping yourself by wasting your time trying to convince people that some long dead boy-king was black.
They are basically waging this fight so that they can add a one liner to a textbook for a college black history class.
A big part of "Afro-centric" education is teaching that Egyptians were "black", thus making them "one of us".
I had a guy at work once who was going on about that. He was unhappy when I pointed out that, since there was no record of Egypt having contact with West Africa, it was unlikely there were Egyptians in his ancestry. OTOH, since I'm Italian, and there was a huge amount of commerce between Egypt and Rome, with Egyptian sailors having italian girlfriends, and Roman merchants bringing home Egyptian wives, I was much more likely to have Egyptian ancestry than he was.