The question of why Jared Lee Loughner started shooting up the Tucson Safeway, killing six people and putting a bullet in Rep. Gabrielle Gifford's head is just that: a question. It isn't known whether he was a member of any larger group, even self-identified. The YouTube videos credited to him are pretty much entirely incoherent, except for containing actual words.
That said, something has to change. The discussion in this country has been too much driven by people who don't really know what they're talking about but are willing to threaten violence. And to use it, as is obvious now.
The graphic near the bottom of this page is a perfect illustration. (Stay classy, Sarah.) If you're going to communicate to people in metaphors about hunting and rifle sites, you need to make sure they understand metaphor.