Why China doesn’t accept foreigners as citizens?

China does accept foreigners as citizens, but very difficult because the resource per capita is much less than the world average. Europe has a territory larger than China but only has a population of about half the size of China. America has a territory about the size of China, but its population size is just the remainder digit of China’s. The cultivatable lands per capita of America are seven times larger than China’s. Canada has a territory area about the size of China’s, with a population of about five that of Hong Kong. Developed countries have combined populations about the same size as China’s, occupied territory between three to four times China’s territory, and their military power and financial power enable them to control world resources beyond their borders.

It is natural diffusion law that people migrate from high-density places to low-density places, just like you put a drop of ink in a bottle of water, the ink will spread to the whole bottle as time passes. It is very unlikely that all the salt of the Atlantic condenses on the American shore and left Europe with a freshwater Atlantic shore.