Because he's a democrat. 'Rats always yell. Haven't you noticed? It makes them sound like they're righteously angry instead of just pimping the boobs in the audience, and it fools the boobs into thinking they're serious. They share an image of themselves as embattled defenders of the oppressed (notice how they're always "fighting for' this that or the other cause?). It's all bunk of course, but the boobs in the audience lap it up.
Interestingly, this charming character shows up here and there in NYC, accompanied by guy who yells a rant into a PA system. When it was in my neighborhood, he was protesting some construction company. So I think it's safe to say it's a union tool.
If this rat could make you vote for someone, I think we all know who it would make you vote for.
I thought he was going to have a Reverend Wright moment.