I think it is stalking and harassment when a cameraman (or two) follows a person around constantly when they are in public. I think it is harassment to publish photos like the one discussed here, as it is part of a larger pattern of humiliating, following, photographing and trying to get shots like this. Just because it happens in public doesn't mean it isn't stalking or harassment or an invasion of privacy.
BTW, I'm not the one who came up with those terms in the context of paparazzi. You know, I'm not a fan of celebrities. But I am against anyone being harassed. I feel these people are harassed and stalked by cameraman:
https://www.youtube.com/watch?v=KhByqJeXNag
If someone followed you like this and took photos of you and put them on the internet, you would call the cops. And it doesn't matter that no one would be interested, in your mind. You'd be freaked out. Is that the problem? Is it okay because she's attractive or wealthy and thus deserves it? Does society think this kind of activity is what celebrities deserve? That they have lost their rights to be treated decently?
Perhaps Kate and company are not that bothered by this one incident. But the problem is greater than this one incident. It is the constant following and photographing and screaming out questions and blocking, etc., that is the problem. It is the lack of decency in general in society that causes us to think this behavior is okay or that the publication of such photos is okay or that causes us to click on such a photo.
It is shameful to think that because she didn't wear a weighted dress, it's okay for a news agency to publish a photo of her naked rear end.