All countries have a variety of cultures. The U.S. has Alabama, New York City, Utah, Hawaii, the Bay Area, etc. You can always find a way to split people and set them against each other. There's the West; Europe and other Western nations; the UK and other countries; England, Scotland and Wales; London and the rest of England; different parts of London; different religions and ethnicities, the punks and the mods, etc, ad infinitum.

But I don't see any purpose to that. You also can unite people and get great things done together, as 13 very different colonies did in 1789. Why choose fighting with that alternative?

> you may even have heard about a sizable war in the past century that was predicated on cultural differences

I disagree. The cause of the war was one country trying to conquer the other ones. And each side was composed of countries of different cultures and languages. Germany, Japan and Italy; and the U.S., Russia, France, China, etc. on the other side.

And in fact, the EU was created to prevent another war; togetherness has succeeded: The idea of war inside the EU is now absurd.