Koppel would like to bamboozle the American public into thinking these villagers are completely isolated from the outside world.
Nonsense. Somewhere in that village is a TV, and Hanoi is very good about broadcasting international news (my wife's relatives even knew about the DC snipers).
They know who Kerry is. And they know he was in Vietnam.
Even if they're NOT isolated, where are their diaries, their after-actions, ANY paper trail to back up what they're saying--or, as so many others have pointed out, proof of the photographic memories?