I think it's questionable whether the modest dress actually achieves this goal of being less sexed up. Aside from the modest dress, my understanding is that women are discouraged from going out alone in public. So in addition to the habit (er, whatever you call it

Burka is it? ), the women you'd see in it, are vastly outnumbered by males in public. This seems an overly harsh restriction on women's freedom, out of proportion to its supposed benefit.
I have not been to a nude beach, although I've heard that in nudist communities, the prevalence of nudity actually diminishes people's obsession with it - the more they are around it.
The bottom line for me is:
1. I don't agree that sex is a bad thing, though I'm willing to entertain the possibility that reducing people's fixation upon it, may be beneficial in certain contexts.
2. I disagree that
only women have sexual attractiveness. And I disagree that they are/should be, passive with regard to their interest in men as sex objects.
3. I think people should be free to go naked or shrouded as befits their choice of adaptation to temperature, regardless of social context.
Dress is a spectrum. We should no more require nudity, than we should require total enshroudment in clothes. Both Muslims, and Westerners - in fact most cultures, regard nudity with a certain degree of shame. Shame is an important and useful means of social control - but too often, sex has been scapegoated as the sole source of shame. While Muslim's are uptight about showing a little wrist

, we're uptight about showing a little nipple. The only restriction on men is to keep their equipment in the hanger, until NASA (er, women), give them the go ahead for launch, usually in a non-public context.
Somewhere in our evolutionary heritage, we developed self-consciousness about nudity as we lost body hair. But this tends to manifest itself most greatly as part of organized religious social traditions that are often more restrictive of women, than they are of men. Some day we'll come out of the 12 million step program we have been in, and accept ourselves and each other as we are, clothed or not. Before then though, we'll probably see Muslims and the west unite in WWIV, against a common enemy - nudists.
