Why didn't the UN protest Xi Jingping's declaration as 'President For Life'?

China's constitution was changed and now, officially, the current president can rule for life. The president Xi Jinping is now the uncontested ruler of China for life. This is an amazingly unprecedented move on his part. This means that his ideology and plans will be the way the country will move in the next decade or more, according to how long he will live.

The United Nations now other nations do not seem to have protested this bold move to remove the term limit for the government of China. This is possibly for the reason that it is not in their domain to question an independent country's policies as long as it doesn't interfere with the affairs of other nations.