Probably has to do with the billions of dollars invested in Afghanistan at the moment.
What billions? Afghanistan is a vast tray of, well I won't say that, sand with some beautiful mountains stuck in it. Put together it is probably not worth a third of downtown Peoria.
Just a guess on my part. I agree that the media will pick and choose these things, based on a lot of external factors, not all of them particularly commendable. The media, for example, often highlights missing white women in the U.S.A. If a black woman goes missing, however, most people don't bat an eyelash. Unless she's pregnant. I was recently surprised that CNN would bother with running a story on a missing black woman, until I realized that she had one in the oven. What can I say? The media is as biased as any entity.
I think you will find that, in so far as this exists at all, it is a product of their audience's tastes, not media bias. White people don't care about missing Black women. There are too many of them and their stories are too complicated. Missing White girls are easy and simple and White people can relate.