I've read a couple of Jared Diamond's books and find him a bit to PC for my taste.
I agree with you about Jared Diamond, his conclusions are at times questionable, pushing some of his arguments a bridge too far in my view, and his exposition is very much PC. So far as this article though, I think it's an excellent overview of African demographics, but doesn't feature anything I didn't already know. That's not a bad thing - I enjoyed reading it and anyone who hasn't studied the history of Africa should get a lot of good info from it.
Mr. Diamond makes wonderful points, and I like his writings. I agree, he gets a little too PC, but still he makes some great points. I loved the whole analysis of the continents on an east-west axis vs. north-south axis in his Guns, Germs, and Steel.