How Come?

Why are there so few pie-ers targeting leftwing bigshots or really extremist bigots? Even the left leaning bigshots on the list - Chretien, Dion, Pettigrew - are not accused of extremism. As much as I think pieing is a really stupid way to get a point across, I'd like to see someone with the stature of, say, Mohamed Elmasry, get a pie in the face.