This is a striking image, the girls looks to be a 14 going on 40, and the boy, perhaps, wants to stay young. Lots of ways to interpret it, and yet, I think, it's obvious they've had difficult lives. She really did capture something in that girl's eyes!
The exploitation issue comes up from time to time, because there's a perception that a photographer can show up someplace, rattle off a few snaps and be on their merry way. When, in fact, it's quite time consuming to gain the trust needed to achieve this type of image. It's rather hard to photograph human suffering. And, honestly, Mark has probably made very little money on this image. Images of human suffering are, indeed, quite hard to sell. But, as Don quoted, their stories have no chance to be told if she doesn't make the photoraphs. I think she supplements her income doing a lot of commercial work.
Oh... and that is Ansel Adams! Don't you just love the hat?