Recently I watched a video by CGP Grey called This Video Will Make You Angry. It reminded me of a blog post called The Toxoplasma of Rage which I had read.
The basic idea is that ideas (memes, as Richard Dawkins called them -- not caption graphics, but self replicating "idea viruses") compete for survival, and that ideologically opposed memes (for example radical feminist and antifeminist memes) can work together symbiotically for mutual survival in the idea ecosystem.
How does this work? By producing a cycle where getting enraged about the opposing idea produces behavior that draws more attention to the idea.
The sad result is that by engaging in polemic attacks against a bad idea, you may often end up promoting that idea even more.