They are Americans, that is the reason. From a young age they are taught that they can do no wrong, that the nation is based on only glory and greatness, that the US in their holy sacramount special greatness only dropped bombs to save people... (in reality, the same treaty of peace offered before the bombings was the one accepted by the US after the bombings, the Japanese never surrendered their emperor even though the propaganda in the US said it was a complete surrender afterwards, this is taught in schools to this day) or how the Pilgrims left England because they were oppressed when in reality they left because the were not allowed to oppress and burn people alive for not being of their faith in England.
Then there is the Civil war that the US fought gallantly because of oppression when in reality it had to do with England abolishing slavery in England and in all colonies and the American colony wanted their slaves to stay so they got French to fight for a reason that was a complete and utter lie...
Basically everything about American history that is taught and cherished is an outright lie.
But hey... 'murica! Drumph, Capitalism... Much intelligence, such thinking... hurr...