Quote Originally Posted by mad pierrot
I would say it might be Japan's isolation, but it has had more than ample time to grow accustomed foreign culture.
Especially that countries like Norway, Finland, Ireland or New Zealand are not less isolated, and probably all (but NZ) have less foreigners than Japan.

Why does it still persist? I don't know. After being in the education business for a few years now, I have suspicions. Teachers are perpetuating many of these myths, that's for sure. (I was giving a presentation on American not too long ago, and heard my teacher announce to the class "America isn't humid.")
Education certainly has a lot to do with it. Especially that it is controlled very closely by the government, which wants to make all their citizens feel that Japan is (superiorly) unique in the world. That's indoctrination. Japan and China aren't that different regarding government and education. The way they proceed is the same. The difference is the content (communist propaganda in China vs "unique culture and country" in Japan).