My intended point, I’m not sure if I was suitably clear, is that ‘diverse cultural identities’ and ‘getting along’ have fundamental compatibility problems; not merely a vulnerability to distortion or exploitation by the especially ill-willed.
You can certainly have a broad diversity of cultural practices, so long as some details are agreed on(and you can also have rather ugly conflict among people that outside observers would be hard pressed to tell apart if they are not); but unless you have a fairly weak flavor of ‘culture’, something more akin to the ‘lifestyles’ sold in magazines, in mind; you can’t really paper over some contradictions.
The cultural differences you can’t really compromise on are quite often the ones that are relatively low visibility; and the ones that get people frothing about the filthy Xenos are often amenable to trivial coexistence; but they are there, even if people often get confused about which ones are which, or simply enjoy demanding conformity on all matters.
I, say, probably resemble your average American Dominionist reasonably closely in speech, dress, appearance, diet, etc. Certainly more closely than I resemble members of a wide variety of immigrant groups. However, it’s impossible for me to share a government with a Dominionist(luckily, it’s currently the Dominionist whose culture is substantially ignored when it comes to law and government, so we don’t have a theocratic hellhole on our hands); while it’s comparatively simple for me to share a government with someone who appears much more alien; but is also interested in constitutional democracy.
