double ironically, your comment precisely answers your question

the two of you operate on different scale of unification - what you see as "many different cultures", chinese and americans see as "a single country". What they see as "Europe pulling in many directions" - you might see as independent national interests

perhaps the best way to recognize the attitude is to think what you feel about subsections of your country - while Scotland/England divide is common, it's rarer to hear in what Yorkshire differs from the Cornwall; and I bet not many people would guess what beef is there between french citizen from Normandy and from Nice

it is this kind of scale that allows China to build transmission lines through the whole country's diameter. It is that kind of scale that made americans scream at each other because of abortion high court decision - while said decision simply said "let states decide"

it's a lot of difference, and there's a lot of nuances "on both sides" - but simply of a different kind