lol, his liege was a total douchebag.
It was common, look at the way the King of France often treated his vassals the Dukes of Normandy and other powerful Dukes. They would often play them off against each other to ensure none became too strong, and thought little of expanding French land into their Duchies when the opportunity arose. William the Conqueror learnt much of the methods he used to subjugate the British nobility from his own treatment at the hands of the French King when he was younger. This idea of a true chivalrous relationship between liege and vassal is more a romantic dream of later ages then a wide spread reality.
