I am from the UK and expat but unlike you I have spent more than 10 years in one developed country, not bouncing around many of them. I speak and understand the language (not natve level but my job is in English). I have now spent enough time here (just) to somewhat disentangle the national persona and stereotypes from individual people's personalities and get used to a host of ideosyncratic ideas and behaviour.
Before you write off the rest of the non-US world,think about how much time you spent in each place compared to the time you spent in the US growing up and normalizing your viewpoint with the rest of the US people around you.
I think the reason you didn't feel you belonged is that you didn't belong. When you do, you do.