Unaccustomed Earth (in more ways than one)

So I'm reading Unaccustomed Earth by Jhumpa Lahiri (great book by the way, every time I pick it up I don't want to put it down) and reading some of the accompanying press that is generated when an author has a new book out...and I am wondering why the media has decided to doggedly pursue the same line of questioning with regards to her writing.

Everyone either asks or refers to other people asking her why she only writes about immigrants from India and their children...as if there is something wrong with that. She is the child of Indian immigrants. And to be fair, her characters are Indian, Indian American and Caucasian, so there is some variety.

No one asks African-American authors why they mainly write about black people. They don't even ask Amy Tan why she keeps writing about immigrants from China. And no one ever asks white authors why most of their characters are white.

But there are a different set of expectations for "minorities" and within that perilous category of minorities, there are different expectations for different minorities.