The paper says about those, "Behavior which a listener perceives as possessing any of the characteristics listed in the left-hand column arouses defensiveness."

The paper says about those, "Behavior which a listener perceives as possessing any of the characteristics listed in the left-hand column arouses defensiveness." So the author doesn't describe it as defensive behavior, and he's not even concerned with it as behavior, only as a perception that might arouse defensive behavior.