The whole thing's stupid because, apparently, no one in charge told the person handling the casting to exclude darker people. And, as the article also points out, not all Hobbits are necessarily pale white. The "browner" Hobbits probably wouldn't be found in The Shire, but this shouldn't be that much of an issue for it to be a big deal if there were some in the movie.
edit: Looks like the person responsible was fired.