I guess this is primarily a historiography question, but I whenever I see a reference on reddit to the US winning WWII, there's always someone around to deny that it happened. Did it become culturally important in Europe to exclude the US from its victory narrative? Is there some historical basis for this?
The statement that the US won WW2 in itself is disrespectful to the other nations which were allied with the US. That the US was a couple of years late to the party doesn't help the perception either. Indeed, the Russians in particular would take exception to the statement, given that they were pleading for quite some time for the Western allies to do something against the Germans before finally they got around to it (not that the delay was unjustified). The Soviets also were responsible for the vast majority of the German forces destroyed, the German force ratio on D Day of Eastern and Westrrn fronts being nearly 10:1.
However, of course, that's far from saying the Us had no important role. The US had the lead in the fight agains Japan, and were the dominant combat force in Western Europe. US supplies of materiel was similar critical to all nations.
So, in a nutshell, the world would have had a vastly more difficult time winning WW2 without the US, but the US on its own didn't do it either. If the Soviets weren't fighting, the Western Allies likely couldn't have done it without the A Bomb.
Part of it is the way Reddit conceives of WW2 to begin with. Its a mostly Western User base, with significant European populations.
Which means half the war is excluded, with the war against Japan in many measures being the larger conflict, with an overwhelming contribution from the US.