Matthew Yglesias has been wondering why the Taliban are more popular in parts of Afghanistan than we are. There is no real mystery about this.
In Afghanistan the average American soldier does not speak the local language, does not follow the local religion and is unfamiliar with the local mores and customs. Furthermore it is American policy to forcibly transform Afghanistan in ways many locals find highly objectionable. So it is hardly surprising that American soldiers are not universally loved by the locals. Our native vassals have more local knowledge but are constrained by having to at least pretend to be following American policy.
Ann Coulter notoriously suggested that the way to deal with places like Afghanistan was:
We should invade their countries, kill their leaders and convert them to Christianity. ...
I don't advocate this but if we aren't willing to use such methods we shouldn't be trying to transform Afghanistan as this just makes us unpopular without achieving anything.