I'm still at work, so I don't have the time to craft a full reply to all of that . . .
You raise some good points and, like I said, I don't mean any of this as a put-down of Eastwood's film, which I haven't seen. But I am bothered by the implication of some movies today that World War II was all just soldiers on both sides doing their duty. If you read any history at all, you know it was very much a war of aggression by the Germans, Italians and Japanese aimed at extending their dominance over other countries. If you don't like what's happening in the Middle East today (and I assume by the remark about the Bush administration that you don't), then you would have really been upset by what the Axis powers were doing in the 1930s, long before the US ever got into the war. Moreover, the general populations of Germany, Italy, and Japan embraced the claims of their superiority over other peoples as Hitler, Mussolini and Tojo were coming to power, so they bear some responsibility for what happened.
To say an individual Japanese soldier couldn't feel these things because Japan as a NationState or whatever percentage of its officers and soldiers were guilty of war crimes strikes me as silly. I'm not saying that's your argument, just wanted to make that clear.
I haven't seen Fires on the Plain either, but I gather from your description that the cannibalism it portrays is among starving soldiers trying to stay alive. Well, that's happened before in desperate groups--shipwrecked sailors, snowed-in immigrants in the Old West, even a South American soccer team whose plane crashed in the mountains. But that's not what I'm talking about--an insane act by men driven insane by conditions beyond their control.
The type of cannibalism I'm talking about is a ritualistic cannibalism of enemy soldiers by Japanese officers who still had access to normal food and drink. The idea here is not survival but the assertion of superiority over defeated foes. This is well documented from the war and is described in the book Fly Boys about Marine and Navy pilots who were shot down over an island adjacent to Okinawa, I believe (don't think it was Iwo Jima). The book talks about maybe a half-dozen pilots and aircrew who were shot down and captured by the Japanese held for several weeks, then eventually killed on orders of high ranking officers who then ordered some body parts cooked and served at ceremonial dinners. Soldiers were ordered to remove a liver or strips of meat from the torso for that purpose. One officer insisted his other officers eat this, although few actually wanted to.
Anyway, the fact that the Axis had SS murder squads killing civilians in Russia and Italian aircraft were straffing and bombing native villages in Ethiopia and the Japanese were using live targets for their soldiers to shoot and bayonet--in other words systematically involved in attrocities on an large and organized level, I do think the Allies had legitimate claim to a somewhat higher moral ground in that conflict.
Here's one of the clearest examples I know: I once saw a TV program in which an old Japanese man who had been a boy living with his family on Okinawa told of the Japanese soldiers telling the large Japanese civilian population on that island to kill themselves to avoid being tortured and horribly murdered if captured by the American soldiers about to invade that Island. This old man told how he and his brothers used rocks to beat their mother to death to spare her such a fate. Later he was captured by the Americans and of course was not tortured and not killed. But he had to live his whole life knowing that his own army had caused him to murder his own mom for no reason.
At that same time and on the American side of the battle line, there was a young Marine, a Mexican American from the barrios of Los Angeles who had been taken in and raised by a Japanese-American family and who used his knowledge of Japanese language and customs to go out alone and talk enemy soldiers and civilians on Okinawa into surrendering. Risked his own life to save the enemies of his nation. He was credited for bringing in thousands of Japanese soldiers, which is why Okinawa was the only island in the Pacific where the Japanese didn't fight to virtually the last man.
Now to me, that illustrates the basic difference between the American and Axis armies, particularly the difference between Americans and Japanese in that war; I've yet to find a documented account of a Japanese soldier saving Allied soldiers. That's why it bothers me when a movie like Memphis Belle opens with a dedication to "all airmen" of World War II as though there was no difference between us and Nazi Germany and Imperial Japan.
Years ago, I did read a book--don't know if it were a novel or an actual journal (but I suspect it was a novel) translated from Japanese about a Japanese doctor who was drafted into the Imperial Army and sent to a Pacific island during World War II. He too was a humanist, not a soldier, and the book contained many entries about home and country and honor and the men with whom he was stationed and the officers that commanded them. It put a human face on the Japanese soldier in an interesting and enteraining way although it didn't ignore the differences between US and Japanese culture at that time and the brutal ways in which Japanese soldiers were trained and treated. It's well documented that pre-war indoctrination and training of Japanese soldiers started at a very early age and was extremely brutal. Enlisted men could be beaten or killed by their own NCOs and officers. They in turn were brutal to anyone they got under their control. It was a definite mind-set that too many people today ignore in assigning a blanket "they were all soldiers doing their duty" forgiveness to both sides. There are some "duties" that just shouldn't be done.