Why can't you CYCLISTS use the sidewalks?

Get off the road !!!.. Its annoying having to wait in traffic for eons just because of you. I promise and I honest to god mean this, I'm not bluffing, when I get back home if I see a cyclist on th road blocking me I will either touch him sidewards with my car, or drive so fast in front of him he either DIES !!!!!!!!!! or goes on the sidewalk.