I will call someone an Englishman, but I will not call someone a Chinaman. I've had friends from that faraway land whom I called Asian, Chinese, but not Chinaman.
Quite the society we live in. Things we say in a blue state might not fly on a red state. Learn to adapt that's the beauty of this nation of ours. Technically you're right Chinaman is a person from china, but the moment you cross into the realm of technicalities, you enter Asshole nation.
It's complex, but not. Don't stress it out, let it ride. Years ago we were told that everyone is equal, and now we're told to think of their differences, what makes them special. The extremes of a pendulum, swinging away.