Mark Schacter has a posting on the Luminous Landscape website titled, Am I a Photographic Cheat? Of course, this is a rhetorical question. Schacter doesn't think it's "cheating" to use a digital camera and employ Photoshop to create an image that becomes the equivalent of what he saw and felt. In his words, "The only discussion that matters is about what it takes to produce good photographs that viewers linger over and remember. Whether we use cameras that capture light on film or electronic sensors, some element of manipulation will be involved in producing good photographs and will always be integral to the creative process."
We manipulate as soon as we frame an image in our viewfinder, limiting what's inside the arbitary boundaries of our sensor and excluding what's outside it. We manipulate by chosing an exposure that favors some details over others. We manipulate by chosing an aperture that ordains the depth of field. We manipulate in choice of wide angle or telephoto, thereby determining the spacial perspective rendered. We then further manipulate when we decide to capture in jpeg or camera raw. All this is just when we trip the shutter release. It's why we're called photographers and not robots.
The point is, we make decisions every step of the process from lifting the camera to our eye (or deciding what will be on the ground glass screen), to the final output of the image for public viewing. This is what an artist does. It's no different than saying a musician manipulates a musical score by translating notes encoded on paper into sound waves of various frequencies and tempos.
The final output is the result of something outside of us passing through the magic inside of us. No two photographers will produce the same image of the same subject because each photographer is a diffferent feeling and thinking human. Each brings the unique array of experience, skill, vision, emotion, and spiritual energy to the undertaking.
My answer is this to those who object that digital photography is manipulation: Get over it, please move aside, and let me get back to work.