Kevin,
You know that I am very pro-British, and certainly respect your efforts during the war, both before and after we arrived at the party a bit late. My answer to your question, why does Hollywood take pot-shots at the British in WWII movies, is very simple: Monty's extremely poor PR capabilities. Remember after our long discussion of old Monty in July, I agreed that he was a competent comander, but that personality wise he was a class 1-A-1 A-Hole. Look to history: Monty had a big mouth. He loved bragging about his accomplishments, denegrating his competitors, and was not above taking credit for other people's successes. As a result, he thorougly pissed off virtually all of his American allies, and that anger still exists. It is far easier to get an American to complement German generals like Rommell or Guderian than it is to complement Monty. And to us, he is the face of the British forces during WWII. So yes, American movies constantly take pot shots at Monty, and viewing him (incorrectly) as an incompetent as well as (accurately) an egocentric putz, we project that image on the British forces who served with or under Monty.
Is it right? Absolutely not, and I have repeatedly taken the side of British and Commonwealth forces in these debates, and deservedly so. Heroic, competent and well led (most of the time), the forces of Britain and its Commonwealth carried the water for the free world, pretty much alone, until Hitler launched Barbarossa and brought the Soviets in on our side.
But will Monty ever get a positive portrayal in the American media? Not bloody likely, and deservedly so as well. He treated Americans like bumpkins, talked down to us in the media, so he will always be a hated figure here, no matter what he did to defeat the Nazis. Remember, the enemy of your enemy is not always your friend.