What if one of those "morons" takes out a big sign with the text "Beware folks. This photographer will stick a camera in your face, take ugly photos of you and posts them on the internet". He follows you with this sign for the rest of the day through the city. I bet this is absolutely legal in most countries and he is even telling the truth (except the "ugly" of course").
What would you do? Of course you wouldn't complain because that's what you expect from others too, right?