I can see both sides of this but, I am leaning toward a degree of agreement with the author.
That said, we are talking about degrees.
This is obviously photoshopped: http://www.anvari.org/db/cols/Photoshopped_Animals/Photoshopped_Animal_07.jpg
But, if I claimed, either as an outright lie or a lie of omission that it was a "photograph", I would be misleading you.
To a lesser degree, to claim that I got this great shot of Yosemite Valley with an amazing pre-storm sky, when, in fact, that sky was shot over a municipal dump in Amarillo, Texas, is that too not a lie?
You could argue that you are publishing an image and not "claiming" anything but, that what is the title of the image? Does it make the "deception" clear? Does it need to?
As I said, I can see both sides of this but, I do feel that the art form has reached a cross roads. With ever more powerful tools, the world is open to a skilled software user but, should skill with software be given apparent parity with work in the field and a skilled hand on the release?
Taken a step further, do the images you use even have to be your own or is the act of editing others' images where your claim comes into existence? For example, I grab two images in the public domain. One is of a gorgeous sunset in Hawaii. The second is of an Asian mountain range. I artfully (and I am obviously being hypothetical as I am barely passable with editing software) combine the two images. Is that now my image? Should I be able to sell it as such?
Perhaps, we are at a point where there is photography and there is digital imaging. One requires manipulation of images captured by the artist and in the same location and during the same shoot. That is photography. The other one is use of digital images in any way the artist desires. That is digital imaging.
You guys have sold far more pictures than have I so, I will defer to you from the artist's point of view but, as a consumer of art, I believe I have a right to know what I am buying and I believe that mediums need to have some distinctions.