ok.. here are the facts..
Taliban : bunch of ignorant dirty primitives.. most of them even dont know what they read and what they believe..marry together the girsl of age 8-9.. nothing on earth can change their minds , even if you blow up their heads.. Russians tried and gave up

(at that time US was giving them best of guns )
US soldiers : they really dont know what the hell is happening in those hostile lands.. and the regions culture and civilizations is 500 years behind them.. but killing all the Afghans is not the solution apparently.. and furthermore its not their war which I said many times..
and political facts: US searching/cleaning for Al queda and extremists in that region is pure 'dangle berries'.. everyone interested with politics know that the region is very close to oil fields and controls the back door/mountain passages to Asia and Russia .. so US wants control over it.. no matter what the costs is.. all other reasons are secondary..