At the same time, my chinese family has never considered me fully chinese. Shoot, even my mom is losing full chinese status among my uncles for marrying two white guys and not visiting HK enough, even though they all moved to the US at the same time!

This dynamic often has nothing to do with what your actual physical/cultural bg either (bc racial cats aren’t real fixed “essences”). For example, growing up in TX, I was called “chankman” for years by the white folk, even though the Herndons had been in US and TX longer than those calling me slurs.

"how is it that someone could fail to realize that 'African-American' here does not necessarily refer to an American person from Africa, and that 'African' also does not necessarily refer to a person from Africa?"

no idea man, the world's a strange place

maybe more obvious to me as a child of immigrants socialized around other such people but categories here are not even used consistently by people who were socialized here - possibly because they don't actually make sense. it's quite possible that people from elsewhere just actually don't understand

just saying: if you didn't grow up crafting a default answer to "what are you/where are you from?" with some version of "what do you mean?" you may want to consult people who did about what's going on here