Do you not understand US-China tensions? Both countries fear each other, and someone who’ve lived in the US for practically their entire life suddenly wants to visit China? That’d definitely raise some alarms about a potential spy. Maybe nothing happens, maybe they falsely assume I’m a spy.
Same thing when I return to the US, those border agents are gonna ask me why I went to my China during these times of high tensions.
There are risks from both countries. Whereas if China was democratic and US-friendly, none of these would be an issue.
Do you know how many people in the US were falsely arrested? That’s in a democratic country. Think about those odds if it were an authoritarian one.