You may be getting misled by the apparent albedo ~ which is many photos is similar ~ just the luck of being a public man I guess, but color or tone means nothing when you are out there among 50,000 black people and you are looking for Dick Thompson ~
Give you an example going the other way. I have so many red headed relatives it would not work at all to try to find any of them in a crowd by looking for red hair. So, i look at the 72 other significant points on the face and ignore the hair! At the other end I worked in a building with about 3,000 employees. I personally knew every single red head and could meet with them in a single conference room (if need be). Just looking for a redhead in a crowd of USPS headquarters employees would usually suffice.
Trust me when I say that I've got a better than average ability to differentiate one black face from another. People in my family run the gamut from white enough to fool you, to black as Nat King Cole.
The albedo doesn't throw me off. I'm looking at eye shapes, noses, mouths, chins, jaws, foreheads, cranial shape and size, ears, cheekbones -- things like that. Skin tone and hair color don't matter a whit.
Heck, my little sister, who is a dark chestnut brown, is a dead ringer for our grandmother, who had white skin, blue eyes, and blond hair. I was just looking at their pictures today, as a matter of fact. It's stunning how similar they look.
Now, I'm not saying that Malcolm X really is Obama's father. I just think there's a possibility that he could be. As far as anyone knows, Obama was built in a lab.