In his continuing examination of why Hollywood’s recent antiwar films have flopped (even though the old Vietnam stuff didn’t), Roger L. Simon offers a very interesting explanation. The Iraq films flop because they lack the same type of passion which characterized the anti-Vietnam war films.
As Roger explains, it’s a lot easier for leftists to be pro-Communist than pro-Islamist:

While the Vietnam and Iraq Wars are often equated by the liberal-left, the differences between the two are greater than the similarities, especially in the critical area of who is the adversary. For Vietnam: The evils of communism could be and were rationalized by the left as a plea for social equality in an economically unjust world. For Iraq: The evils of Islamofascism and just plain fascism are considerably harder, indeed almost impossible, to rationalize.
This problem is particularly true for Hollywood because the evils of Islamofascism – notably extreme misogyny and homophobia – are justifiably big no-nos to people in the Industry. In fact, they are close to the biggest no-nos of all for them in their daily lives. Who is worse than a sexist pig? Only a violent, murderous sexist pig who wants to take over the world. It then becomes a complex balancing act indeed to make a movie that ignores or downplays this in order to criticize the US as the larger villain. No one has been able to come close to pulling off this balancing act in a film. In fact, it may well be impossible because it is fundamentally dishonest.

I think Roger is right, and it shows in the quality of the films.
People don’t want to sit through fundamental dishonesty. It’s also emotionally unrewarding to go to a film expecting good guys and bad guys (after all this stuff is marketed as entertainment), only to be told that “your side” is bad, without a cogent and compelling explanation of exactly how the enemy is supposed to be good.
Would Hollywood make a film showing American troops committing atrocities against the Nazi SS in an unsympathetic light? Such things did happen; I knew a man who was present at the liberation of Dachau who personally witnessed American GIs spontaneously shooting unarmed Nazi concentration camp guards despite the fact that they had surrendered. The officers didn’t stop it as fast as they might have, for they were also in a state of horror over what they found. But there’s no question that shootings like that were illegal. For obvious reasons, such incidents tended not to make it into Hollywood films. They’d have flopped at the box office, and to make them during World War II would have been unthinkable. For that matter, so would a film about the deaths of innocent children during the firebombing of Dresden.
Whether war is war, and whether atrocities in Iraq are morally comparable to atrocities against the Nazis — these issues are irrelevant to whether the general public wants to shell out money to sit through a scolding of their own country.
To the extent that entertainment becomes propaganda, it tends to lose its entertainment value. To make good propaganda, the propagandist has to be what is called a “true believer.”
(Such a thing may be an oxymoron in Hollywood today.)