I have thought about this at some length.
In your sentence:
For the most part, I am certain we can agree for all practical purposes, these particular (in-camera) image manipulations result in a picture we except as an authentic representation of what we saw through the viewfinder.
—the word “except“ should be “accept.”
Except that my feelings, when I take a picture, are nothing like that at all. I have a vision of what the final picture will look like, and I try to craft something in the moment that I take a picture that will get me to my vision. The more of the work that is done when I snap the shutter, the more effective I was at that point in time. It is a question of craftsmanship and process, not whether the end product is art, or acceptable, IMHO.
I think I may get where you are coming from though. For me it is like trying to distinguish a bush from a tree using only language, but perhaps an order of magnitude greater in difficulty than even that. For me, the end result if one has gone too far is nothing more than a private or internal eye-roll from me, having in mind that the person next to me may be deeply moved or intrigued by the same image.
I started on film and dark rooms. I was thrilled at the advent of digital photography that the same concepts of light and movement and composition could apply. The same applications of shutter speed, depth of field, contrast, grey, color, shape, lines, balance, motion, etc. But I see no need for a talented young one to think as I do. In fact I would be delighted to learn a young one thinks nothing like me at all, and creates art with these new visions, and new techniques.
I went to school on a campus with painters and classical musicians, stunned by their hard-won skills and talent. I respect the painter, the musician, with such painstaking skill, such care and practice, and so much left to feelings and judgment and love and imagination. Why would I strip these powers from the photographer, reduce him or her to a craftsman, if he or she aspires to art?
And I know that I am no more than a craftsman, and a mediocre one at that. I have seen and known the artists in the flesh, and have too much reverence for what they have achieved, to think otherwise.
So you could put me in a box you reserve for those who do not agree with you, if you wish! And close the lid, if you must!
Just my two cents.