If I may quote:
"we do understand their culture. And it is almost completely at odds with ours. Hence we should be out of there. The Taliban were doing a pretty good job of suppressing the drug trade; much better than we're doing anyway."
Exactly, they controlled their internal situation with reference to long established religious beliefs. Unfortunately the major export of that country (apart from refugees) is hard drugs - and the profits that then allow certain bodies to continue their influence.