I think that it shows that while Norah O'Donnell has heard of the vague Israel lobby, she doesn't understand it that well. That is why she asked those questions the way she did -- she's only got a very weak grasp on the issues at hand. Appropriate skepticism, but the amorphous Israel lobby isn't fully an AIPAC top down organization, but more the multicomponent lobby that Mearsheimer and Walt describe that is primarily based (within the Jewish portions) on shared ethnic identity and values as well as (within the religious right portions) on shared religious conviction. I personally find nothing wrong with their resignations, in fact, it gives more media coverage to the book in question.