There's a short but illuminating article at Media Matters for America on the prevalence of violent imagery and metaphor by those appearing on Fox. You can find it here: http://mediamatters.org/research/201002040060
The problem with the comments cited in the article are not that they are passionate or political. It's not even that some of them are downright hateful. It's that they play with the imagery of violence. "Figures of speech" are not mere ornaments or funny little doo-dads we add to our speech; they are ways we frame our understanding of the world. Cognitive linguistics suggests that metaphors in fact structure the actual neural pathways in our brain.
That is, words mean things. Not in the sense that they have timeless, unchanging definitions. They don't. But they have consequences. They have implications. They do things to us when we speak and hear them.
Should such rhetoric be censored? Of course not. But they should be censured--condemned as unworthy of consideration by thoughtful people and out of bounds of civil talk.
