There is nothing immoral about this. This is not a moral issue.
Photography is a big fat lie, and it lies beacause of the focal length of the lenses we use, or the sensor size, or the colors rendered by the film, or sensor, or lens. A lens can make a fat person less or more fat depending.
There is very little truth in photography, so what is the big deal here? What, a revealation from God the OP had here?!?
This is completely true.
All photographs are lies. A photograph can no more tell the whole truth of reality than a cup of seawater can tell the whole truth of the ocean.
Aside from uses for which pure recording is necessary, such as the aforementioned police forensic and photojournalism (and it's a knee-jerk reaction even in the latter), this is an issue only for you photographic johnny-come-latelies who don't know anything about the history of photography.
Major image manipulation began as soon as photography progressed to an interim negative process. One of the most famous portraits of Abraham Lincoln taken in 1860 actually has Lincoln's head composited on another senator's body. Another famous Matthew Brady photograph of all of Lincoln's generals had one general added who was not present when the original group photograph was shot.
Photographers began heavily manipulating photographs for artistic reasons from its very beginnings, specifically to combat the accusations from painters that photography was nothing but mechanistic reproduction--not "art." The early Pictorialism Movement was all about manipulating the image as much as was technically possible. That eventually caused its own backlash--the Realist Movement (championed by the f/64 Group)--but even the Realist Movement believed in manipulating the image by any means necessary to force the image as it looked to the eye, not as the camera reproduced it.
There was never an ethic of not manipulating images, not even in photojournalism. Some icons of photojournalism, such as W.Eugene Smith, were known to work on a single image for days in the darkroom to make it look as they saw it, regardless what the camera actually produced. Beyone manipulation, there was always the issue of posing subjects, moving objects, framing, timing, et cetera in photojournalism that made it clear that honesty was a matter of the photographer, not the camera. A dishonest photographer can lie about a situation just as easily by simply choosing the framing, direction, and timing of his shot.
Manipulation has always been part of the photographic art. This "get it right in the camera" stuff began only in the mid 60s as color took ascendence over black and white, and that was only because color was too difficult and expensive for most photographers to retouch. It was a matter of economics, not ethics.
So now Photoshop returns the art and craft to where it always had been. You newbies need to get over it.