Does fourth-generation Okinawan mean that her great-great- grandparent moved out of Okinawa and yet still consider oneself an

It seems like the article is using the fact the author is a fourth generation Okinawan to frame her as an authority on the subject, which I don’t think is valid.

All the second generation Europeans I know call themselves whatever citizenship they have adopted. They don’t learn their parents language, instead strive to be integrated into their new country.

Can someone explain the American habit of keeping track of being 1/8 Irish or a 4th generation anything? I can’t help but see this as a vain attempt at being unique and interesting.