Why did chivalry fail to protect ordinary soldiers and civilians in earlier wars?

Chivalry did not protect ordinary soldiers and civilians because it was an exclusive warrior-culture designed to bond the aristocratic class, rather than a universal humanitarian code.1

The system of chivalry was fundamentally tied to the status of the knight—a fully armed, mounted warrior. This culture served to distinguish the nobility and lesser fighting men from those who labored, a group that included peasants, artisans, and merchants. Because chivalry was built on the shared identity and military interests of this elite warrior class, its rules of conduct, such as forbearance and honor, were primarily intended for interactions between peers of similar rank.2314

Furthermore, the protection offered by chivalry was often limited by the realities of medieval warfare. While the code theoretically promoted virtues like generosity, in practice, it often excluded those outside the knightly order. As the Middle Ages progressed, the ideals of chivalry increasingly shifted toward aristocratic display and ceremony, further distancing the knightly class from the common people who suffered the most during conflicts. Consequently, the "honourable" conduct associated with chivalry rarely extended to the protection of non-combatants or lower-ranking infantry.421