You do see the difference between a thought, shared with no one and visible to no one, and an image on a computer, which can be uploaded to the internet, right? This isn't about stopping sexual desire, it's about not distributing images of someone's naked body without their permission. That it's not a guaranteed accurate representation is sort of beside the point. It's good enough if you've never seen them naked before. Some people have gone on record saying they don't like it when it happens to them. Why, do you think?