If you want to get all academic about it, I am coming from a position of virtue ethics, which is why I am focused on the vicious men who purchase sex, and to a lesser extent other people who are explicitly or implicitly defending those men's actions.

And all the more if it's a billion prostitutes in an eternity of misery supported by a malevolent AI!

Alternatively, Alice could consider the possibility that Bob is not, in fact, an idiot.