The difference between one monster and the other is that one monster is a threat to her husband's cock primarily and the other is a potential threat to her son-in-law's cock.
Moreover, can you guess why a young woman who was getting her undergarments stolen by a guy would have to clobber that guy? It probably wasn't because he was being very nice.
It's not even that deep. There's a few versions of this story where choosing the precious axes gets you killed for dishonesty. You have to assume that the only correct choice is the original axe.