While the focus on Afghanistan tends to revolve around geopolitical tensions and security concerns, the slow erosion of the urban middle class is sending the country decades backward.
It's possible that China was also concerned about Pakistan hosting an American official in areas adjacent to Xinjiang. China has long claimed the northern valleys of Jammu and Kashmir as part of its larger strategic sphere and important staging points south of the Himalayas. Beijing anticipates that Pakistan will seek her permission before allowing US officials to enter such sensitive areas.