No one is blaming the east africans for people not caring about the sport. It's not their fault the rest of the world can't keep up with them.
It doesn't matter WHY they don't give great interviews or show much personality to the public. All that matters is that they DON'T.
It also has nothing to do with race. If they were all blond Norwegians or something, yet none spoke any english, and it was an entirely different crop every week, and no one could pronounce their names, I think you would see interest wane as well.
People need someone to root for or against in order to care. And in order to know who to root for or against, you have to either get to know them in some way, or be able to discern one from the other. When they all look mostly the same from the press truck, even down to the uniform, why would I care? You can only run so many world records.