Take a look at the success of the Civil Rights movement. Do you think segregation would have ended as quickly had black activists simply stuck to laws and elections, and not protested and deliberately did things that were actually illegal: like sitting in the front of a bus or disobeyed police orders to disperse while protesting?
The extra-legal actions of the protesters and the brutal response of the authorities (all documented through the mass media) made way more people aware of their cause and gained them many allies.
Or take a look at all the labor activism in the US, back when unions were strong, which brought about things like the 40-hour work week and workplace health regulations: these were not won merely through elections.
Or look at the Suffragettes, who helped win the right for women to vote not by restricting themselves to winning elections but by direct action.
Or India's successful struggle to independence under the leadership of Gandhi. Once again, it was coordinated activism which made the difference.
The list of such successful activism could grow very long.
Which isn't to say elections are useless (though with all the easily hackable electronic voting machines and vote counting machines out there, sometimes I wonder), but to reject activism in favor of elections is to give up a very powerful tool for change.