How is it counterproductive? By what mechanism does complaining about the mainstream media actually make it worse? Complaining about the mainstream media may indeed fail to improve it, but saying nothing will certainly have no effect.
Of course it will. Don't consume it.
However, most of us probably do tend to influence the opinion of a few others. A little complaining (in a constructive way) might be useful, albeit in an indirect way.
I like to think of preaching to the choir (or disagreeing with them) as being a way of polishing one's persuasion prior to the full congregation (or converting the masses).