Nothing is quite as invigorating as jumping up and down and yelling at someone. So the citizens of New York City took the opportunity of Ahmadinejad's visit to the United Nations to curse him out with placards and bullhorns. Whee! Wasn't that fun?
But it accomplished nothing. So what? You're rude to a visiting foreign leader. It does nothing but help Iran's leader to be seen being yelled at by Americans. The next time, do something useful. Welcome him. Be polite. That would be a little harder to explain back home and Americans wouldn't look like ranting idiots.