When you see who's really running things over there, it starts to make sense. The only people with real continuity are a few general officers (doing 2 year tours) and a ton of civilian "senior advisers" (some have been there for 9 years now) to our military. These are all ex-military people making a ton of cash working for companies like Dynacorp, MPRI, L3, etc. Since their pay scale works something like: Retired O-5 $300k\yr, Retired O-6 $450k\yr, Retired O-7+ $700k\yr+, they're heavily incentivized to keep the war going as long as possible. And since most of the military is rotating out every 6 to 12 months, the only people that really know what's going on are these contractors. And the senior military officers aren't going to rock the boat because they see themselves retiring from the military and taking one of those sweet contracting jobs themselves in the near future.
And if you dare to point out that you're duplicating efforts from years gone by, essentially working in circles to no avail, you'll be threatened (by a civilian!) with an early return to the US. Guess how I know. :\
But once you stop asking questions and learn to enjoy the raw simplicity of the lifestyle and country, and the frontiersmanship of the whole experience, it's somewhere between enjoyable and exhilarating. You just can't overthink what you're doing.