Why are americans so arrogant?

No offense to anybody, but these yanks often tend to overstate their importance. They often rant about "liberating" Europe from nazism, eventhough the russians are the ones who broke the back of the german war machine. They claim victory in the "space race" against the russians eventhough the russians got to space first. They are unaplogetic for twar crimes abuses in the Iraq War such as Haditha and Abu Gharaib. And they often bagger others about the need to "talk english" evethough their English leaves much to be desired. (As an englishman, I can testify to this). The question is, how much of america's arrogant patriotism, and nationalism is a result of ignorance and mis-information of the outside world? Only 21% of americans have pports and fewer can identify nations on a map. Maybe americans feel for this excessive patriotism/fascism because of constant mockery from the rest of the rest. Perhaps this arrogance is a defense mechanism.