This is just one of the many things surrounding this absurd war that I fail to understand. So as a tribute to briefness I shall only point to some of the main incongruencies I find.
DoD is funding the Taliban, whom they are suppossed to fight, because they can't beat them in the ground. This money is handed to "contractors" through the army that is supposed to fight the Taliban (if I were a field officer, I'd surely be pissed off ). The bribes are paid in order to secure US bases with the provisions needed. Top Afghan goverment officials (puppets) are part of the scheme, since they are all relatives, and part of the same illicit association.
So to make it short, why doesn't the US government consider buying off the Taliban, something that would prove to be a far cheaper way of having them controlled, and with the side benefit of stopping the blood drainage of its soldiers.
Forerunners of this attitude can be found in deals such as the purchase of Alaska or Lousiana, just to mention a couple.
War is a very complex achievement to be left in the hands of the military. What you need is counsel from your accountants, and don't worry about the possible "moral" consecuences, since there are numerous precedents in your near history.