In small defense of those who abandoned their families, it is possible that this salvation through the medium of the women was precisely what was hoped for when Noah and the others abandoned their wives and children. Perhaps there was some tradition of non-violence against women that they had recognized. Certainly those who stayed with their families rapidly turned to a different version of the same ploy. Where Noah would have abandoned the women and children, perhaps supposing that they would be spared, the men who remained with their families still used their women as intermediaries rather than put up a fight.
Mormon's interpretation is that it was the beauty of their women that softened the hearts of the Lamanites. It is hard to understand how a marauding army would be touched by beauty to the point of forgiveness. It is quite probable that this was a negotiated surrender. While lives were spared, capture was not, and the final point of the story is the subjugation of the land of Lehi-Nephi to the Lamanites.