Europe, the US, Canada, Japan, and S Korea are all incredibly nationalistic to varying different levels.

How do you know someone's a European? They tell you all about how Europe is better than America?

How do you know someone is american? They tell you all about how great America's freedom is?

Japan is one of the most nationalistic countries on the planet.

So is South Korea.

Your claim that these countries are 'internationalist' is based on a flimsy understanding of their self-interested cooperation.