It's not a rational reaction, but I would feel that he had rejected the beauty of African-American women. I just think that he will have a lot to offer, and other things being equal, I would prefer that it go to a black woman. I would be upset if the black guy chose to exclusively date white women. This would be an indication to me that he thought white women were superior to black women, and that would be offensive. The concept of personal privacy differs here, an outgrowth of the close-knit features of the society you spoke of.
Homes are closer together, people sit closer in restaurants, stand closer in line or on the subway.
Many homes and apartments are half the average U.S. size or smaller, and people just take this as a matter of course - it's normal here. My own apartment is rather old, but it's of comparable size to many units Japanese families with small children live in. To be honest, I haven't a clue how they manage - I just need more personal space, a little more privacy. Whether this tolerance for proximity and smaller living quarters would affect the incidence of claustrophobia, I don't know. I am white and currently living in Japan.