The marked countries all had their respective asses saved from either the Nazis or the Imperial Japanese army primarily by we corrupt, mean, selfish Americans in WWII.
Although I share your view that the world owes America a debt of gratitude for our defense of civilization and the values of Western Civilization, I have to point out that the Brits had pretty much turned the corner in Africa and Europe while the Ruskies had done so in Asia. The Nazis were going down. We just made it happen sooner with less Allied bloodshed.
If you are cool, you don't have to tell people. They just know.
Now if you want to talk about the damn Ruskies we can talk about saving alot of respective asses...