Why do Americans have such a misinformed view of World War Two?

I see that a lot on here as well, it annoys me a lot. Even in some of these answers people are still putting down our effort. Saying we would not have won without them, I think we would have eventually but it would have taken longer! I think the americans helped a lot and sometimes people do put down their war effort as well but they did not win us the war, it was a team effort!