As far as I'm concerned, documentary photography is the most powerful type of photography there is.
You can't get the same emotional impact, as you can from documenting a real life situation. Sure you can stage things, and documentary photographers have been riled in the past for staging some shots, but the fact of the matter is, they were there, they're opening YOUR eyes to what you would otherwise be blind to.
They chose to photograph a dying soldier instead of helping him. Is that ethical? Age old debate. They're there as an eye to the situations, not as an aid, otherwise they'd go as charity aid.
I personally welcome any picture that shows me a world outside my own fluffy, protected, local city. Because in reality, life is far more grim than we'd like to know, and for people to risk life and limb trying to show us that, I can't fault their ethics.