I agree that it's certainly not the only way to get something. However, if you're trying to make a statement by not voting, your statement gets lost in the noise. If it were not for your enlightening article, how would I know that one less voter this election season was making such a statement? I wouldn't. Most non-voters abstain for other far more trivial reasons. If however I saw one additional vote for Mickey Mouse it would bring explicit attention to your statement.
Voting for Mickey Mouse isn't begging the system to let me be free because I know without a shadow of a doubt that Mickey Mouse stands no chance to win. All it does is make obvious the fact that I'm pointing my middle finger at the system.