Cindy K. answered 05/07/19
Top 1% Tutor, Pro Photographer & Certified Expert in Lightroom (ACE)
We retouch images to make the image look as beautiful as it did to us in person. We filter out so much when viewing something live, but the camera captures it all. Scott Kelby, world famous photographer and arguably the inventor of Photoshop training, explains it in his TEDx talk entitled "Why We Retouch People in Photoshop."
The extent of acceptable editing also depends on the purpose of an image. If I'm creating an image for a interior designer and there's a non-functioning lightbulb on the scene, I can "light" the bulb in post. But, if that image were for selling the house, I could not because doing so might misrepresent a defect with the outlet or wiring in the property.
You may also want to explore copyright law. Ownership of the copyright includes control of derivative works. As with all matters of copyright, derivative works are complicated, but might speak more to the heart of your question.