I suspect that Nod was thinking of the sort of street photography that takes pictures of couples kissing, people crying at graves, war memorials etc - it may be legitimate in that its in a public place , but it could still be argued to be an invasion of someones privacy - ie taking their private moments and publishing them on the internet
But their are quite a few very famous moment in history of photography,where grief has been showed,to great effect,we're theses photographer wrong ?
The problem also is we live in a very emotional age,where sometime every emotion is played out on tv show,day in day out.
It's alway a hard one,when do you press that shutter and when you don't,we know most paps are in for the money,most don't pretend otherwise,their just in a way feeding a market,to most of us it's not a market we would buy into,but it's their.