I feel sorry for the american soldiers. trying to evacuate people makes you defensless and the terrorists took advantage.
The biggest mistake the americans made was to think the taliban is an army of disciplined soldiers who follow orders. The taliban has a core of people who follow orders and then the rest do their own thing and they can't keep security or know how to deal with people. They are good at gureilla warfare but discpline is not one of them.
Before America can deal with the Taliban they need to get on a call with baradar and co and tell him who is in charge. Until the taliban leadership has total control over some of their men, you are going to have terrorist attacks continuing in afghanistan