Human beings...*ALL* human beings...are hard wired to prefer the company of their own kind. That is not a bad thing...it's what allows societies to prosper culturally and economically.
But Japan has a fertility rate of 1.8 and South Korea 1.6. You need 2.1 babies per woman to sustain a population. Unfortunately, those two countries are on paths to extinction.
I think SK’s fertility rate is the worst in the world.