The Mother Jones article has an interview of one of Loughner's friends. While the point the friend is trying to make is Loughner wasn't political the person's own words seem to belie that sentiment.
Loughner would occasionally mention Giffords, according to Tierney: "It wasn't a day-in, day-out thing, but maybe once in a while, if Giffords did something that was ridiculous or passed some stupid law or did something stupid, he related that to people. But the thing I remember most is just that question. I don't remember him stalking her or anything." Tierney notes that Loughner did not display any specific political or ideological bent: "It wasn't like he was in a certain party or went to rallies...It's not like he'd go on political rants."
Note the person doensn't say when Loughner believed Gifford had taken a "stupid" action, but states the "stupid" action as a fact of which Loughner relayed to others. Further more the friend speaks of another friend buying a gun. I hope someone takes a look at this group of young men and what they are up to and how it may of been an influence on Loughner. I suspect here is where one will find a direct link to the politics.
http://motherjones.com/politics/2011/01/jared-lee-loughner-friend-voicemail-phone-message?page=1">MJ Article