It has nothing to do with political correctness. These attitudes are ingrained in Asian cultures for thousands of years.
You’re the one who’s being political correct. You’re the one who is making the assumption that “all cultures are essentially similar”, that when Chinese Americans cheer the warships of the PRC, that it’s no different from a WASP American applauding the Queen of England. When in reality they are completely different, they are completely different because Chinese culture is *not* the same as English culture, and the motivation behind the actions are not the same.
What is the different motivation then? This ship was a guest of the United States. And Americans went out to greet them.