Because it makes them feel different and unique and special and as if they are in a position to talk over Japanese people in regard to racism and appropriation.
I’ve seen this come up multiple times when a white person is backed into a corner accused of appropriation or something of the sort. Living x amount of months or years in Okinawa does not make you Japanese and certainly doesn’t give you a pass to act like you experience the same issues we do.
>Living x amount of months or years in Okinawa does not make you Japanese
I guess this is true if you don’t have any other linguistic, cultural, political, or kinship relationship to the community there. Still, the Amerocentric way you’re framing this really bothers me. On one level yes, of course, that military brat would be an asshole. On another level, your language would be also be at home on the reactionary right when considered in a domestic Japanese context.
The implication that Okinawa/Ryukyu does not count as the “real” Japan is hugely problematic given its people’s long and enduring oppression at the hands of the Japanese state. The Japanese government deposed the Ryukyu Kingdom and annexed its territory in the same series of conquests which included Korea and Manchuria, eradicated the Okinawan language through shame and physical force, used economic policy to create Okinawan ghettos (クブングワァー) on the mainland for cheap labor, and continue to use Okinawa as a base-heavy sacrifice zone to protect the majority Yamato people from contact with the US military.
One of the main ideological weapons that the Okinawan people can use to ameliorate their situation is the idea that they are part of the same ethnopolitical group as other Japanese and therefore entitled to equal treatment. Yamato people have historically reaped the benefits of Okinawan oppression and continue to do so; they are therefore not in position to be casually suggesting that “Okinawa is not Japan lol.”
There also also some pretty ugly implications in the idea that no amount of time spent in Japan can make you Japanese; these seen most easily in the intense racism toward Japanese-born ethnic Korean and Chinese people. So many people are harmed by the completely ahistorical notion that Japan is a monoethnic country; this is not the case, and centuries of effort by the Japanese state have not made it so.