Why does the Left trash the military?
I believe that the Left does NOT support our troops. It pities them. The Left considers our soldiers to be the victims of the bourgeoisie (society's wealthy capitalists, i.e. Halliburton, Big Oil, the Military-Industrial Complex, etc.). The military, in their view, is a relic, a use-only-in-case-of-emergency federal police force, or a job program for civil servants. If a soldier is forced to actually wage war, then he is now a victim, a tool, of the powers-that-be.
Thus to pander to the proletariat, working-class, victims, the Left swoops in to rescue them from the evil ilk of Dick Cheney, Donald Rumsfeld, and our current military leaders. They grieve the "senseless" loss of our soldiers, not as fallen heroes but as the victims of a lost cause. Therefore, slamming the military and what it does makes sense… sort of.
[Thanks to Blackfive and MilitaryMotivator for the heads up.]