J. L. Bell has an interesting follow-up in Oz and Ends: Shelving and Marketing in the Dark:
Johnson perceives this as Borders’s choice, but it looks to me like the decision started with her publisher, Agate Publishing. It issued Racing the Dark through Bolden Books, “Agate’s imprint dedicated to publishing both fiction and nonfiction dealing with the African-American experience.” Though it’s unclear whether the “islander” heroine of the book has any connection to “the African-American experience” except as a reflection of one African-American author’s imagination.
Of course, the hardcover was a Bolden book as well. But Agate is now emphasizing Johnson’s ethnic identity more than before.