Benjamin was well aware, for children this young, especially the ones who lived in a conservative environment, had never interacted with other ways of thinking, adopted a completely different concept than that of the Church priests.
Having fought against mages to this very day, the teachings of the Church had evolved into a rather advanced stage, so much so that they could counter any arguments, making it difficult to win against priests through words alone. But for small cults like this, they definitely do not possess flawless logic in their teachings.
In a sense, Benjamin may had defeated these two on a spiritual level.