He's hates the government. He complains about the money system in incoherent rants.
He wrote for example as the description of a now removed Youtube video (the other crazy videos from after he started talking about himself in the past tense are far later):
Top secret: Why doesn’t the people control the money system? Their Current Currency(1/1) / Your new infinite currency (1/~infinte) This is a selcte information of revoluntary thoughts! Section 10 - Powers prohibited of States No State shall enter into any Treaty, Alliance, or Confederation; grant Letters of Marque and Reprisal; coin Money; emit Bills of Credit; make any Thing but gold and silver Coin a Tender in Payment of Debts; pass any Bill of Attainder, ex post facto Law, or Law impairing the Obligation of Contracts, or grant any Title of Nobility. No State shall, without the Consent of the Congress, lay any Imposts or Duties on Imports or Exports, except what may be absolutely necessary for executing it's inspection Laws: and the net Produce of all Duties and Imposts, laid by any State on Imports or Exports, shall be for the Use of the Treasury of the United States; and all such Laws shall be subject to the Revision and Controul of the Congress. No State shall, without the Consent of Congress, lay any duty of Tonnage, keep Troops, or Ships of War in time of Peace, enter into any Agreement or Compact with another State, or with a foreign Power, or engage in War, unless actually invaded, or in such imminent Danger as will not admit of delay. Each subject is unlocatible!
Yeah, he loves "grammar" and wants gold or silver backed currency. That's as close to a motivation as I could fathom. He's a grade A nutbar. When ever I google somebody like this they always end up being completely insane.
And this video is going to be rocketing thru the blogs.
Though the shooter's incoherent rants don't seem to have a lick of politics. There's the fiat currency thing, but that's more crazy than political.
Upon reflection and a report that he was "very political in high school" and a commenter on Facebook pointing out that crazy is just a dismissive view and most schizophrenics and bipolar people are not any more prone to violence. Yeah. I'm going to go ahead and allow for the clear possibility that it was in many ways politically motivated. He reportedly met the congresswoman in 2007 and called her "unintelligent". Usually when high school and community college drop-outs call people such, it means they just don't like that person. I doubt such people have the judgment needed to make a proper assessment. He's seeming more tea-party wackado as time goes on. Especially if one considers that pretty much all fiat-currency conspiricists are extreme right.
Update 1- 10 -11: Nope, he's just a nilist. His dislike of currency is because of nilhism. Since it's fiat, it's pointless and worthless and doesn't matter, go ahead and make your own. Blah blah blah. He's actually one of those fiat-currency people who isn't necessarily extreme right. He really just didn't care.