Having grown up in a country where nationalism kind of harks back to nazism, it's always weird for me to see all the flags everywhere. It's just not something I can get used to, even after all these years of seeing US flags everywhere.
Americans' proclivity for displaying the flag is a way of expressing unity in a country that doesn't have a common ethnicity, religion, or language.
Nationalism also facilitates integration in a country that has tons of immigration. My family is from Bangladesh, where group membership is determined by ethnicity. A white American could move to Bangladesh at a young age, speak the language fluently, marry into a Bangladeshi family, but he'd never be Bangladeshi. Here, you step off the plane, put that flag up in front of your house, and boom you're American.
Americans ask precious little of immigrants: learning the language, waving the flag, etc. In contrast, in almost every country where there is a majority of "brown people," there is nothing a foreigner can do to integrate. Had the situation been reversed, and I was an American immigrant to Bangladesh, people would always stare at me and call me "bideshi."
Yup, that's why we've never had a brown president.
Also I would request to pause the "you step off the plane, put that flag up in front of your house, and boom you're American" for some time. The meaning of "American" is currently under active and violent change.
Minor nit, it was more "culture" or "ethnicity" than language, although language was perhaps the most defining feature. It seems that the Punjabi Pakistani's looked down upon their (then) countrymen of Bengali heritage.
https://youtu.be/J-7j6O_whYA?t=1m8s
I transcribe the key part here (1:08-1:48):
Nisar: We had a great bureaucrat, a senior intellectual, Qudratullah Shahab who has a book called Shahabnama (an autobiography). (he relates from the book) In the 1950s, the Americans had given, as was their custom, sanitary goods as charitable donations in bulk. In a few cabinet meetings, Bengali ministers said "Let us have a share from this." The potbellied, large mustachioed (this is a Punjabi stereotype) West Pakistani ministers made fun of them and said "What do you lot need a commode for, you can go behind a banana plant" This was the manner of dealing with them.
[0]: https://en.wikipedia.org/wiki/Archer_Blood#The_Blood_telegra...
Had India not been separating the two, it would have been much easier for West Pakistan to use repression or other means to hold down Bangladesh as long as they'd like.
They don't feel the same as they did when I was a kid, and there are more of them, and they're used in different contexts.