Because...
It's a strange thing, but photographers with a modicum of photographic ability often fall flat on their ass when it comes to writing about the work of other photographers.
Not sure why I missed this - probably too much excitement over at the photo-chain thread.
Anyway, I was wondering why the sentence had been written in italics - was it a quote from something?
Regardless, it may well be true that photographers don't necessarily write well about the
work of other photographers, but then very few people ever do: the temptation is to the extremes: either they praise them to the heavens or knock them, but that, of itself, doesn't mean that the praising or demolishing isn't being done well.
Perhaps the truth is that there is not a lot that can be written about the photographic aspects of the work of photographers, but much that can about the effects of that work on the writer. Describing the graphics is pointless when they are plainly visible - or lacking - right there in the image. Much like food or perfume, they depend for effect on sensitivities other than those that lend themselves to words, making the writing project far from easy.