Exactly. And it's not as if he wrote a whole series of political essays expounding his views on dozens of topics; as far as I know, this is the only essay he wrote while in prison.
I don't know enough about the evidence for an Iraqi connection to venture a judgment. Still, a federal building in Oklahoma seems like an odd target for a proxy campaign against the US.
This is true, and I'm not reaching any kind of judgment here. But Iraq's possible motivation is clear: they would have been hoping that this would ignite the militia movement (or the "right-wing patriot" movement -- I'm not sure what name to use), dragging the U.S. into civil war. In fact, it did the opposite, because the bombing discredited the militia movement in the eyes of the public; many sympathizers realized then and there that violent revolution, which might have sounded "romantic" to some in theory, was an ugly path that they did not want to follow in reality.