Why can you get an American hukou if you are born in the United States, but not in China?

Each country's population identity policy is based on its own specific situation. China has been an independent country with a long history since ancient times. Neither the occupier nor the aggressor has been able to quit or assimilate, and every nation has a long history. It is basically closed. The United States is an immigrant country, and its ethnic composition is very complicated. There are Europeans, Indian aborigines and African blacks ... The special national conditions have created special policies. An open country with serious racial discrimination.