[Jack Black]

You could also say uni-cultural society, vs. multicultural society. Less identity politics.

You could. The existing term is "ethnostate". Japan is an ethnostate, meaning it is made up of people exclusively (or overwhelmingly) of one ethnic background: Japanese.

There are still many ethnostates in the world, but they are shrinking. Poland and Iceland come to mind.

[USFRIENDINVICTORIA]

Thanks for the useful new word.

Now, when I discuss Quebec politics, I can say something like: “Les Quebecois want Quebec to be an ethnostate; while the rest of Canada is rushing headlong into multiculturalism. That's one of the root causes of separatism.”