it's not different in the US, there is not a market of misinformation about WWII here. There is the the anti-war left alleging that that the allies committed war crimes and their opponents rejecting those arguments, but it's easy to find what happened in Dresden, Holocaust, etc, the disagreement is on interpretation.
The allies most definitely committed war crimes - the Red Army was pretty brutal in Eastern Europe, for example, for literally no reason. As for the Americans, there is certainly ongoing debate as to whether the nuclear weapons dropped on Hiroshima and Nagasaki were really necessary.
Fire-bombing a city full of civilians is probably also a war crime. Tokyo was not a giant aeroplane factory, it was full of Japanese citizens who we would consider innocents, "Grave of the Fireflies" is about that period† - the children literally starving to death isn't an exaggeration for the sake of making a sad movie - that's the reality of what we did to win.
Not to mention the US literally rounded up citizens who had Japanese ancestors and sent them to concentration camps. They apologised, decades later, but note these aren't enemy civilians who happen to be in the wrong place, they're your own citizens who merely look similar to the enemy.
Because the Americans sent babies to these camps for the crime of having ancestors born in Japan there will be a decade or so of people who have memories (albeit fuzzy ones) of this actually fucking happening to them after the people who fought WWII are dead.
† Grave of the Fireflies is set in Kobe, which was also fire bombed.
[Edited to specify that Grave is in Kobe]
Yea, it's not really the left that's the big proponents of this (maybe a few very fringe people). It's the ones literally given Nazi salutes at political rallies.