The practice of ‘pixel peeping’ is, within itself, not necessarily the object of ridicule as much as it is the glorification of technical perfection (particularly that which is often imperceptible under normal viewing conditions) over the image itself.
Moreover, machines designed to save human lives need to function perfectly. Photos, on the other hand, do not need to be technically perfect to succeed, on the contrary. In fact, placing such perfectionist demands on all photos would be mind numbingly ruinous.
As for the jeweler analogy, one might say that ‘pixel peeping’ would be more akin to a jeweler using a microscope, rather than a loupe, to inspect the rock, but I reckon that’s up for the debate.
But again, it’s not the practice that draws derision as much as it is the exaggerated emphasis on technical image quality that can potentially overshadow the compelling nature of the overall photograph.
As someone on here said years ago, pixel peeping is like looking at a billboard from two or three feet away. Ultimately, nothing wrong with this, as anyone has the right to view the world the way they want to.
That is, it is not to say that such perfectionism in image quality doesn’t have its place, and I myself usually increase a photo by 200 percent or more while cleaning dust and scratches from film scans.
Still, when photographers become more consumed with what their photographs look like at the subatomic level (and it’s their right to do so!), then they’re going to be subject to some ribbing.
But seriously, for the sake of newcomers, I find it inadvisable to even remotely suggest, even if unintentionally, that the quality of their photograph remains unauthenticated until further inspection via pixel peeping.