This is just another case of the triumph of marketing over reality... human beings a**sociate diamonds with beauty, we see them as the delicate gifts of a benevolent earth and f***it we like shiny things.
You try being a guy in a serious relationship and getting away with proposing without a rock, it don't matter who she is she is on the sliding scale from severely disappointed to f***in incensed. Diamonds have no intrinsic value beyond a few industrial applications, their values as treasures are completely created, but we always buy into "constructs " with much greater enthusiasm than anything else.
And why was anybody surprised that Russel Simmons isn't an altruistic saint, he's been the epitome of big business for the last decade, he's just the black face of corporate success. Why are we kidding ourselves into believing that his skin tone automatically imbues him with a greater concern for a world far removed from his bottom line.
The history of the diamond trade is an ugly one drenched in blood and built on a foundation of the corpses of poor people, black and otherwise, BUT that is the history of ALL industry. Realise that "exploitation" is a not a dirty word in business, its meaning can be resoundingly positive.
There are no easy answers and romanticism about the effect of a positive message is about as naive as you can get.