Why is World War 2 unique?

World War 2 was perhaps one of the few wars in the history of mankind where the fight was about something more than a political squabble. The War of 1812, WW1, Vietnam, none of these were like WW2. It was the closest we will ever get to a true good v evil war.

Yes, the Allies did have Stalin, and the Axis did have redeeming features, but there was still a clear hero in the eyes of most. It is the most similar to a fairy tale: A noble side fighting in the name of freedom, sovereignty, and democracy, defending the world against an cohort of brutal, genocidal dictatorships.