Insurgents are certainly NOT apolitical. They may wish you to believe that they are, but that contention is untrue.

And Tom, good historians always look at motive. One of the problems I have with contemporary history is that the people you're talking to can easily spin their own actions and motives. The best history examines motive and uses all available sources. Anything else is a sham, or has an agenda of its own. Good examples of this are the "instant histories" that came out after Vietnam, as well as the flood that's being produced by Iraq. Some of them are good, others are not.

Insurgents don’t have a goal of winning although they would not mind seeing their enemy fail.
-from GP's post

This is also certainly untrue. The majority of insurgencies have the goal of winning; that is, meeting their own political goals and objectives. That can be something as mundane (to us) as securing voting rights to something as major as carving out their own nation or "homeland" within an existing nation.

Where I think you're confusing things is that in Iraq you have insurgents AND fellow-travelers who happen to be terrorists. Terrorists thrive on chaos and bloodshed (in many ways it's the only actual goal they have). The two often exist side by side (and within the same umbrella group), and it isn't always possible to get a clean separation between the two.