Because you're unable to understand art, honestly. Photography isn't just "taking a photo and making a grayscale image in Photoshop"; but rather a combination of a couple of different artistic expression styles that involve understanding how to use the tools you have (a camera, the lens, film or a sensor, and lighting) to capture an expression of an event. Technically speaking, a photo of a mountain isn't just a "photo of a mountain" that you would maybe throw into AI slop--but an actual, legitimate photo of a mountain and how it's captured and presented (no matter the post processing done) is an actual artistic expression of the capture of that mountain. Because absolutely nothing, nothing at all will capture actually standing there looking at the mountain. A photo is the best approximation, and sometimes doesn't even have to be, depending on what the artist wants to express with the image.

In short, your inability to understand photography doesn't justify the use of AI slop to prompt "give me a grayscale image of a mountain" and assume that it's the same thing as a human being taking an actual photo. They're not even close to the same thing.