...for shits and giggles that Jared Lee Loughner grew up in a void and the violent rhetoric and imagery that permeates our national political discourse had no relation whatsoever to his actions.
Let us leave aside any notion that people are affected by growing up in a culture in which it's acceptable to a Republican president for his lunch guests to say things like "I tell people don't kill all the liberals. Leave enough so we can have two on every campus—living fossils—so we will never forget what these people stood for," and in which those sorts of things are said routinely and considered perfectly normal, where exhortations to violence against ideological opponents are widely regarded with the same sort of head-shaking, resigned, vaguely amused exasperation as the latest casual disgorgance of racial bigtory from Uncle Fred (as if that doesn't matter, either).
Let's get that perfect world of undiluted disconnection in our heads.
Now answer me this: In that magical world, why would anyone feel inclined to vociferously defend their use violent rhetoric and imagery?
Sure, the answer is "free speech." The objection to the principle of censorship, even self-censorship.
But that's a lousy answer, if you claim not to mean to convey and incite violence with violent rhetoric and imagery.
Free speech isn't about the actual words you use; it's about the ideas that you convey. There are many ways to express the same idea.
The only idea that must be conveyed using violent rhetoric and imagery is violence.