If a fleet wants to harry an attacker's retreat from a station, the attacking fleet should be able to turn around and engage that fleet at no risk of the station interfering. It makes no sense whatsoever that they can do damage to the attacker and gain the benefit of the station's defense at the same time. One or the other, never both.
As the station is a stationary target, the attacking fleet can just slowly creep away with its guns pointed squarely at it. If the defending fleet tries to attack from any other direction, the attacking fleet can fight back it without the station's interference. The only time a defending fleet should be able to harry is if the attacking fleet chooses to retreat from the defending fleet alone.
