Dear Real American, I'm pretty sure my dad stood elbow to elbow with the good folks from Australia and New Zealand when he fought in the South Pacific. I don't think he believes the U.S. won it "single-handedly". What ended the war in the Pacific was the bomb, no question, and yes, it was dropped by Americans.
Also, since you've mentioned the "you'd be speaking German if not for Americans" twice, did you know Americans almost voted German as the official language back when we were setting up our nation? Not your point, I know, but an interesting tid-bit.