It was Bill Gertz who asked Rumsfeld the question that, from what I saw, made Rumsfeld very irritated. I believe, if I could read into Gertz's questioning, that Gertz's concern is that in the interest of appearing politically correct the higher-ups in the military by avoiding the issue of internal jihadis, have made "force protection" vulnerable. Gertz now has an article U.S. fears attacks from Muslims in armed forces.