Perhaps if you are born here you are so tuned to it that you don't recognize it. With the opposite is true, I may not be able to describe it very well, but I know American culture when I see it.
It does have several elements to it, a judeo-christian ethos, a belief in the constitutional republic as envisioned by the founders, and a serious individualism rather than a collectivist one.
All of these qualities are of course being eroded by the Gramscian success of the left in defacing the common identity. A lack of proper civics education, a constant attack on religion and western values and the promotion of collectivist socialism is eroding much of the American "culture" but it's still there.
As I said before, I may not be able to describe it very well, but I know it when I see it.
If I say American culture is a certain thing, then usually there's something that presents itself as an 'exception'. My father said all I needed to know about America that was important is the Constitution and the Declaration of Independence. As long as I can remember, I pretty much worshipped my dad as the American icon. I'm glad for the brainwashing I got as child because I managed to survive atttending college during the late 1990s the height of the PC movement. I happen to agree with your summary as well. The NEA is a terrorist group BTW. There are a lot of kids born here, parents born here American kids black,white otherwise, who are very confused and ignorant about life and have no sense of self thanks to the publik skools.