At a certain point frustration with lack of progress from the avenues you suggest needs an outlet. Demonstrating that there is an active left wing in the US is a useful thing since the viewpoint the US government and the traditional media seem to focus on is either centrist or extreme right wing. The anti-corporate message coming from Adbusters and Occupy Wall St (http://occupywallst.org/) seems to be getting out better through online sources in any case.