I'm an American who has lived overseas and I think I have a little more nuance than this, but overall I have the mindset you describe. I think it's kind of like

I'm an American who has lived overseas and I think I have a little more nuance than this, but overall I have the mindset you describe. I think it's kind of like the factoid that ~70-80% of people say they are better than average at driving. In particular, a healthy level of self esteem helps individuals to perform better because they are more confident and take advantage of more opportunities. And I think "USA is the best country" is a myth that creates the self-assuredness that makes Americans come off as "pushy" to everyone else. In many (but not all) businesses, a "pushy" strategy works well financially. So even though it seems illogical, it's not that attributes of America cause it to be "best", but that America thinking of itself as "best" causes it to have certain strategic attributes. Now, that said, many Americans have a totally unhealthy level of self-esteem that turns into nationalism, white supremacy or near-fascism. TBH I don't know how to deal with those people, but by my logic above it might be more successful to help them consider the impact of their beliefs rather than why their beliefs are wrong.