Some assertions: 1) Men use women's beauty and purity as reflections - if they are with/looking at something beautiful and pure, they feel beautiful and pure themselves. 2) Men do not feel pure or beautiful - I would guess women deal with these feelings also, but they are not at issue in the dynamic I am focusing on. 3) Rather than facing, squarely, their own feelings of being disgusting, tainted, impure, ugly - if morally or emotionally - they seek out women to be their mirror. This creates a pressure on women to be pure. If you are a man and think you are not involved in this dynamic, imagine the difference you might feel if a male friend spat in the street and a woman you wanted or were invovled with spat in the street. That specific scenario might not be the right trigger, but I think many men will find other behaviors that seem more disgusting in women: whether sexual or physical or expressions of desire around sex food or violence. So men have created a pressure - which manifests in different ways in different cultures - for women to present as pure and beautiful and suppress or avoid presenting themselves in ways that remind men of the ways they themselves feel impure and 'ugly'.