I see this all around as well. It's interesting to me how few men actually do show any obvious reaction. In fact, I never see it. When I was growing up and into my teens and twenties .. it seemed that you'd often see (or experience) men turning around when they passed a woman,, or would look at her blatantly, saying something, calling out from a car .. (NOT that this is a good thing, in fact, I hated that type of thing), but I absolutely never observe that anymore at all. You could see the most attractive woman dressed immodestly and you'll see guys walking by as if she's invisible. No perceptable response by anyone. You kind of wonder why women keep doing it when they aren't getting any "positive" feedback!
Sometimes I think that without intentionally trying to, many (even secular) men are forced to practice custody of the eyes (and thoughts too) just to get by in the day to day business of life. I also think that men are both 1) afraid of sɛҳuąƖ harrassment charges, and 2) have become so saturated with these images, that they've become less and less sensitive, i.e., consciously reactive to them.
I know, alaric that you've noticed otherwise you wouldn't have mentioned it. But I think that it's such an aggressive act by the women, ... that most men have just shut off to the stimuli. And frankly, it's like a female version of attack. It's less about sɛҳuąƖity, as it is about power.