Brilliant post. I agree thoroughly. If you haven't read this Washington Post article on the hijab, you might find it fascinating. It supports your argument well. While many wear the hijab as an article of faith,

To us, the “hijab”is a symbol of an interpretation of Islam we reject that believes that women are a sexual distraction to men, who are weak, and thus must not be tempted by the sight of our hair. We don’t buy it. This ideology promotes a social attitude that absolves men of sexually harassing women and puts the onus on the victim to protect herself by covering up.

The topic of what constitutes obscenity when it comes to dress is certainly timely. I wonder if increasing globalism is bringing this topic to the foreground, since cultures vary so widely in the body parts they sexualize. Barbara Kingsolver writes of her capri pants creating scandal in Africa, for instance. Sexy shins!