It's easy to be blase about something you've never experienced. Why do you need this explained to you?

If the Japanese experienced even 1/10th of the levels of Black/Arab immigration the West does there would literally be rioting in the streets. These people view bi-racialism as a novelty -- see how often they describe the people as pretty because they only SEE THEM ON TV -- because as of now it's not an existential threat for them like it is for us. Hence the different responses.

Find me the interview on the streets when Tokyo has the same demographics as London. You'll hear Japanese people saying things that would turn your hair white.