I don't have any philosophical problem with postwork / re-touching and I even make ham-fisted stabs at it myself for Poser or Vue images.   As far as photographs are concerned, I may remove little specks of dust, but doing much more than that seems to me to defeat the object of photography, which is essentially to record what is in front of the camera.   OK - if you have made that once-in-a-lifetime-trip to, say, Namibia and you took a film camera, so you don't know until the films are developed how the final photographs will look, a little bit of repair work is acceptable.   It may be possible to turn a badly taken photograph into a very successful image, but I think that it ceases to be a true photograph in the process.  

Cropping is a separate matter, obviously, as there's no reason why the photographer  should employ the full frame, except where cropping is consciously used as censorship.   There was quite a good book, published about a dozen years ago, called "The Commissar Vanishes", which showed how photographs of Bolshevik bigwigs would be doctored to cover up their having become unpersons.   Quite often, it was done with an appropriately brutal lack of subterfuge:  the censor obliterated the deceased with a black pen.   On other occasions, though, considerable efforts were made to edit photographs, to make the edited versions look seamless and authentic.   There is a famous picture of Stalin with Lenin that is really a concoction from two completely different photographs.   Books covering the period quite often make the mistake of treating it as genuine.

It wasn't just photographs, either.   While the Belomor Canal was being constructed, at a huge cost in human life, Genrikh Yagoda was the big cheese in the secret police.   The slave labour even, it is said, had to create an ice sculpture of him.   By the time the canal was approaching completion, however, Yagoda was in terminal trouble.   At the official opening of the canal, Stalin was accompanied by Yagoda's executioner, Nikolai Yezhov, who was sketched at the scene with Stalin and a few other yes-men for a large-scale oil-painting.   The trouble was that, round about the time that the painting was nearing completion, Yezhov paid his own one-way visit to the Lubyanka's basement, so the painter received instructions to edit Yezhov out of the picture, which he dutifully did.  

In the UK, traffic cameras used to contain film.   Part of the reason for that was that digital photography was in its infancy, but the better reason was that a photographic negative is very hard to fake.   Digital images were not considered acceptable as court evidence, because they could so easily be manipulated.   In recent years, photo-manipulation has become ever easier, but digital images are now accepted in the courts of England and Wales (and, judging by the number of speed cameras between Glasgow and Argyll, the Scottish courts probably don't object, either). 

So I suppose the lessons for Poser-folk are twofold:  don't drive at 65 mph between Loch Lomond and Inverary and don't accept the top job in the Russian secret police.