As a person from the UK and having traveled abroad, I can say that the reason the states acts the way it does is directly related to three things.
1. Puritans
Puritans came to the colonies to escaApe the lack of fundamentalism by the Anglican church. When they pushed for their radical reformation the church pushed back, limiting their freedoms due to their radical version of christianity.
So they left for Holland. Where they found freedom. But their hypocrisy moved them to the colonies because, they didn't want their children to be, wait for it.... Dutch.
Yes that's right those people on the Mayflower, they didn't want to be Dutch. Bigotry. Sound familiar?
Once here they didn't want Dutch, aboriginal people, other faiths and anyone that they deemed LESS than themselves. Segregation, bigotry, intolerance. Sound like muslims in Saudi Arabia? Well that's the same mentality.
So the first issue is that the puritanism that came to the colonies set the tone for the birth of the nation.
2. Lack of learned people.
The colonies were at first a money grab. It was to take land and make some money out of it. Then it was used as a prison. With English criminals being sent here. Lastly tradesmen, farmers and workers came as the entrepreneurs had jobs for them.
None of these groups encompassed a large segment of education. The people who came were under or ill educated and from lack of that they of course did what all poorly educated people do; disdain education and focus on hard work ethics and being a person of their word. Brawn over brain.
Sounding familiar? The hard working American ethic? Yes that's your lineage.
3. 19th century revival fundamentalists, hated of the British and Washington Irving.
Yes I know there are three parts here but they shaped the intolerance, isolationism and jingoism going on in the states.
I'll start with Washington Irving. An author that was/is highly praised in American literature. Why? Because you didn't have really any authors that were producing many volumes. There were none with the ability to write as quickly nor at the reading level needed like Irving.
And best of all he wrote historical fiction a favourite of the states. Real history was dull, but put some drama in and well you get half of ask tele in the states.
Columbus, saying that people believed the world was flat. Pure hogwash. But yanks ate it with spoon. Put it into their education system for years.
Puritans became pilgrims. Never happened. No buckles on hats, no Thanksgiving, no coming here for religious freedom. All fiction.
But here is where the fundamentalists come in. They take Plymouth rock and make it a banner. Marching around the nation, demonising drink, games of chance, certain foods, smoking and pretty near anything that most people do. The lack of people going to church was also intolerable so added things into city, state and county charters to limit the evils of men and promote church worship.
It became so bad that many of these "blue" laws are still on the books, yet not enforced. Why even changing electoral dates to suit their needs. Ever wonder why you vote on Tuesdays when its most inconvenient? Thank them. They wanted to make sure you had time between farming, going to Sunday service and travel time to the polls. And why November? Most crops were harvested by then. Yes religion and agrarianism.
Finally at the time the states still hatred the British. We had the money and was the super power. But still most yanks identified with us felt bad they had no castles, rich history and aristocracy. So they made it.
Robber barons became your aristocracy. Building lavish estates and ruling over vast tracks of land. Rockefeller, Brady, carnegie, Winchester all the American rich. Imitating England and France.
Dickens gave you your white Christmas. The Dutch your Santa, a saint, because well your protestantism killed saints, and you voraciously consumed everything that came from queen Victoria. Even called the era Victorian America.
So these Victorian Americans made the myth of the pilgrims real, taught it in schools and indoctrinated the masses. The poorly educated masses. They tied religion, protestant fundamentalist religion to the manifest destiny and politics. So much so that when Kennedy came they accused him of being with the pope instead of your own people.
The whole beginnings of your nation shaped your current intolerant, insular and bigoted religious institutions. You marginalised all non protestant views and people and that easily allowed you to become cold and uncaring to all but those that towed your line.
Simply put it is fundamentalism that made you into what you are. Its the same thing killing the middle east.