Revolution will happen slowly and hardly, but on my point of vue certainly not by voting through parlementarism and electoral aristocracy. In a way you're right when you believe that voting for nader will change something (let's imagine that 5% of US people vote for Nader: it will put the pressure on capitalists and republicrats).
But non-electoral anarchists are right also when denouncing parlementarism. Firstly because they (and I) want to dismantle the myth of "delegation". Secondly there's the question of making revolution in the activist praxis