It was a massacre. The remnants of a once powerful race stood little chance against the fury of the vengeful Cimmerian. Undulating knives glanced harmlessly off the whirling streak of his restless scimitar. Each time his blade licked out, a dark-robed figure sank dying to the floor. His rough code of chivalry tempted him to spare the white-haired crones; but when the women flung themselves upon him in unrelenting frenzy, he returned blow for blow.
Its quite a stupid line IMO, especially given the situation. If someone, male or female, is leaping at you trying to kill you, you don't have time to consider sparing that person's life. You only have time to react. I consider myself a pretty chivalarous guy, certainly more so than our barbarian friend, and if I a woman attacked me with the clear intention of killing me, I wouldn't pause to think about the moral implications of defending myself.
Its just another example of LSdC turning Conan from a man of action into a philosopher.