Excellent question asked by US soldiers in Afghanistan. Here is an excerpt from a London Times report:
..."Many feel that they are risking their lives — and that colleagues have died — for a futile mission and an Afghan population that does nothing to help them, the chaplains told The Times in their makeshift chapel on this fortress-like base in a dusty, brown valley southwest of Kabul.
“The many soldiers who come to see us have a sense of futility and anger about being here. They are really in a state of depression and despair and just want to get back to their families,” said Captain Jeff Masengale, of the 10th Mountain Division’s 2-87 Infantry Battalion"...
The full sobering but depressing report is here.
There is no such thing as an "honorable" withdrawal when the original strategy itself was wrong: search and destroy when searching is near impossible; fight and hold territory when you cannot possibly hold vast "territory" when most folks are hostile to you; winning hearts and minds when few were on your side to begin with and fewer still when you are supporting a corrupt regime everyone hates....and so on.
There is only a disastrous withdrawal and a cut-loss-before-it's-too-late withdrawal. Ask anyone with any experience in Las Vegas.
Why is it so difficult to understand? One word: pride.