"Because if you did, then you would become a brand. Isn't that what it's really all about - becoming a brand. It might be a journalistic or an artistic or an academic brand, but it's a brand all the same. A brand where the bag and the outrage and the scarf are all part of it. And if you became a brand, isn't that the signal of your complete failure as a human being, isn't that completely contrary to what you or me or any documentary photographer or artist should want to become?"
From this, which you should read.