Defeating a Divine Lifeform was never supposed to be easy. It was even less likely for a greater race to lose to an inferior race when they were at the same rank.
Forest Elves were always known as a superior race. They weren't even stronger than Lesser Humans. On the contrary, High Elves were on par with Hyumans. Some of them were strong enough to reach the threshold of a god. They formed a Divinity and left the realm of the High Elves to pursue greater goals.
Everyone had always said that. The truth, however, was that the High Elven gods were too afraid to stay with their race. They left their people because they were afraid of the Primal. Even now that the Primal had returned to their original purpose and form as the Guardians of the Origin, the High Elven Gods never returned.