Who did Niese think got the dragon's to agree to the pact in the first place? If humans were so inferior to dragons, dragons wouldn't have agreed to form the pact in the first place.
What Logas did was most war provoking. Going against the promise with a superior country like that would've normally resulted in Haim being wiped from the world.
But she is imprisoned for life with the Hero blessed by the goddess. He still is meaning the Goddess approves of the hero's actions. Meaning the Nun has no basis here at all unless she too wants to sin against the Goddess and her Chosen Hero.