Okinawa has its own language. And was assimilated by Japan in the 19 century. Kansai is not a recently added province. Then just look at the policies. How many were built to assimilate Kansai, how many were built to assimilate Okinawa. So difference are bigger that you may think. But i'm trying tell anybody if they are Japanese or not. Japanese people cannot say from one hand that they very different from Chinese people and say Okinawa people are very close to Japanese people. That just doesn't make sense.

> Okinawans are pretty much culturally Japanese

Try saying that in a bar in Okinawa and see how well it goes over.

> a different flavor like Kanto is different from Kansai.

It’s not uncommon to hear people from Tokyo describe people from Osaka as “not being Japanese.”

I’m not saying they are Yamato (trough genetically they have lots of Yamato), what I’m saying is that culturally the differ from mainlanders a bit, but not a great degree.

Okinawa has been a part of Japan for over four centuries, so they’re pretty much integrated and there isn’t much daylight.