Go back and read what I wrote more slowly. I didn't say, "In the United States, there is "right to privacy" for children." I said, "Right to Privacy is already covered in most countries as a valid and fully-enforceable law." and that the paparazzi were taken task, "for the way they were acquiring shots."
Not all paparazzi photos are taken in public places. The ones at question are the ones taken on private beaches, over fences, and more. Also, the new laws cover questions of emotional and physical harm, because the photos aren't standing at a distance calmly shooting. Kids (and bystanders) can get roughed up in pursuit of a photo by a group of aggressive fotogs. I refer to the first quote from a paparazzo in this Time article http://nation.time.com/2013/11/17/paparazzi-crackdown-can-california-protect-the-tots-of-tinseltown/
“I ran across the street and shot her over a wall,” photographer Oscar Rapalo said. “It wasn’t easy. I only had 10 seconds.”
There may be no national law, but California does now have a law protecting the children of celebrities from "intentional harassment" and that's designed to keep a few people out of trees and off walls. It's designed to also help protect their privacy by making aggressive shoots more punishable.
I do understand your argument. Do understand that by the legal nature of the action, there is no way to make the person whole again once the damage is done? The purpose of civil law is to make a wronged person whole. You can't repair a woman's reputation once a naked image of her has actually been released onto the internet by a bitter ex. Also, what other use does the ex have for the photo? He is no longer in a relationship with her, does not have welcome access to her actual body, so why is it then is it acceptable for him to retain the image of that same body for (most likely) sexual gratification (or drawing vicious cartoons on)? A decent person would return it.
In fact, here's a broadly-similar legal issue. When couples become engaged, a man often gives a woman a ring. If they fall out before the marriage, it can be considered a broken contract, and then the woman is expected - by law - to return the engagement ring. So, in this case, a couple is dating, and a man has open access to a woman's body, and they take private photos to share because they are sexually involved. Is it really such a stretch to think that once their sexual contract is broken, the woman should want the man to have no further access to her body in any form?