That's because civilians are (usually) sensible enough not to ask the armed forces to do anything they don't want to do. At least until recently, the professional military have had the cushiest deal in America. They get civilians to buy them anything they want in the way of hi-tech toys. They do no productive work whatsoever. They get to spend their days striking manly postures zooming around in the wilderness, on the seas and in the skies on preposterous, very expensive "training" exercises. And they get health and retirement benefits unavailable to civilians.
Who wouldn't follow "orders" when they entail getting so much for so little?
BTW, Chalmers Johnson had some interesting comments on how the US is being eaten alive but its parasitical military in this recent interview: <http://www.counterpunch.org/engelhardt03212006.html>
Carl