Over here we have several specialized districts, but what you say still stands cause we have 3 chinatowns.
They are like that. I had this Asian friend growing up in our diverse community, now he's "Asian only". Even in facebook. Then I have asian friend from collage, and in his facebook, 2 of us in his list are not chinese. What goes on with the Asian only thing is difficult to gauge. Maybe they know a secret.