I was saying that US requires people who naturalize into US citizenship to take an oath to renounce their original citizenship. This is just a fact and the Supreme Court did not say this is unconstitutional.

Plenty of people have been naturalized into Chinese citizenship, at least in Hongkong. Here is the requirement http://www.gov.hk/en/residents/immigration/chinese/naturalis... and I do see that it requires abandonment of foreign citizenship although it does not say what level of documentation is needed, if any. If it were an oath then it would be symmetric with US. With China ruled by the CCP it is also understandable that the demand for naturalization may not be that high in the first place.