Christopher Anderson of Magnum:
"I have never felt comfortable covering natural disasters. Wars and other types of human-made tragedies are different. There are questions of right and wrong, justice and injustice, political complications, et cetera. I feel like my voice as an observer has a purpose.
"But with an earthquake or tsunami, I don’t have a purpose. There is no need for explanation or contemplation. There is only the immediate need for the news photographers to go and report what has happened.
"I am not a news photographer. I would just be composing pictures of misery. Not to mention being another mouth to feed and another camera in the face of someone who has just lost everything. In the days and weeks immediately after something like this, all that matters is that the news pictures help drive a response of aid. I didn’t feel like there was anything I could add to that. They didn’t need me getting in the way."
And for the sake of an opposing view, here's a video from David Gilkey of NPR: "David Gilkey On Photographing Haiti"