So a guy who is pissed off about his taxes and probably life in general finally snaps and crashes a plane into an office building housing (a tiny portion of) the IRS. He publishes an angry screed on the internet, and now everybody wants know What It All Means.
Predictably, everyone is trying to dissect his manifesto in such a way as to associate this asshole with their political opponents. He was anti-government! He's a teabagger! But wait, he said bad things about George Bush and complained about the health care system!
What all of this ignores is that politics, for all its intrinsic ugliness, is the means by which civilized societies work through their conflicts without resorting to violence. Politics is why California doesn't go to war with Texas over air pollution, or why you and your neighbor don't duel it out in the street if his second-story addition screws up your view. When Joe Stack decided that violence was the only solution to his grievances, he left the realm of politics behind by definition, and entered the realm of crazy assholes who crash airplanes into buildings full of human beings. (That's some mighty fine company you're keeping now, Joe. Enjoy that.)
That, and you really shouldn't try to read too much meaning into the ravings of crazy people. That's how religions get started.