I wonder if the CBS reporter was thinking of Saul hunting David, with the dual subtexts that David never hurt Saul and that David eventually replaced Saul. (Nah, he's probably not that literate. These're certainly popular themes in the MidEast though: "No Moslem would do such a thing as 911.")
Perhaps the true David and Goliath story is that of the Afghan people themselves.
Although it's not a perfect matchup--there were lots of airplanes and ground-pounders wearing the stars and stripes involved--they were the little people who pulled through to an unexpected victory.