The Fallacy: That anybody was a noble actor.
Your wording makes it sound like there's a wrong-headed perception that war is not noble, and that the correction to the fallacy is to find ALL participants VERY noble, valiant and in high regard.
Then, your next sentences:
It was all self-serving. It's often held up as a just war.
The words "fallacy" and "nobody" inadvertently constitute a double negative.
France and the U.K. then caved to Hitler's demands repeatedly and essentially sold Czechoslovakia and Poland down the river to Hitler at Munich 1938, and during the "phoney war". France was then surprised by the swiftness of the German attack but capitulated very quickly. Her armies were still mostly intact when France fell.
It must also be remembered that the extent of collaboration in France under occupation was very great and the French resistance was always very small.
http://www.chomsky.info/articles/196709--.htm
The indescribable savagery of the war, particularly near the end is hard to imagine.
Lastly one of the biggest fallacies concerns Hitler's invasion of the USSR, and speculation as to whether he could have won. The truth is the Germans were incredibly fortunate to do as well as they did! In fact the USSR was a world leader in tank production and tank strategy, before the 1937 purges they had the best and most innovative tank commanders and the most advance tanks. They should have crushed the Germans from the beginning!