Why was Sir Cardoc brought before King Arthur for punishment?

Sir Cardoc was brought before King Arthur for punishment due to his treachery and betrayal. He had been accused of conspiring against the king, which was seen as a serious offense in Arthur's court. This act of disloyalty threatened the unity and stability of Arthur's reign, prompting the king to take decisive action to uphold justice and maintain order among his knights. Arthur’s response highlighted his commitment to loyalty and the consequences of betrayal within the Round Table.