He’s not an ordinary soldier. He does not have to be there. The army could determine that the risks to Harry and other soldiers are simply too great and could potentially create even greater problems if he’s killed, wounded or captured. This is a publicity stunt, plain and simple, to help restore his image after the Las Vegas incident. The military pulls people out of combat all the time for a variety of reasons. This base has never been attacked like this before, and this publicity stunt cost two American Marines their lives.
From his past record, Harry was brave in combat. This isn’t fair to him either, because he is the number one target of every Taliban in Afghanistan.
He was already schedule to go, but after his shenanigans in Vegas, they rushed him off, to put an end to his partying and keep him away from the paparazzi.