I think the moral grounds of this fits in with what you said about art, though. Ads are meant to convey a message (a vision), not portray truth. They are about selling, and using what you need to sell. The photo is just another graphic element of the ad and as such is not confined to realism.

So, what about the regular photos of those celebrities? I’d argue that they are also selling a product, the performer.

And in regular portrait work? I have no qualms about fixing physical features I know a person may be unhappy with, as long as I do it in a subtle way. While many people may say this is morally wrong, clients are usually the first to ask for such touchups.

As for the critique, I think it’s important people sometimes draw attention to it… we tend to forget these images are digital creations and not realistic ideals we should try to attain.