Here's video of him pretty much taking over another groups reasonable protest who are allowing multiple people to speak by yelling and ranting by himself into a megaphone. ]
So, this was a protest he was apparently "joining"?
If I had a problem with what those people were saying, and wanted to discredit their movement and neutralise their effect, I would send in this guy with a megaphone.
It's perfect really. They can't argue with him because he's saying the same things, and his effect is to make them all (himself included) look like maniacs and not rational human beings, thus making it much harder if not impossible to communicate their ideas to other rational human beings. Much more effective then sending someone in to argue counterpoint.
edit: aaaand if I wanted to do that on a national/international scale, I put this guy on CNN with a megaphone..