I was writing this long post asking you to be more concrete, but I realized that this is not my true rejection. On reflection, I think you are right that society is now more tolerant of adultery (sex when one partner is married) and non-marital sex than at times in the past, although it's not clear to me that this has been a one-way ratchet in favor of libertine behavior - compare the 1950s to the 1920s (roaring twenties). Likewise, Victorian era prudishness may have been a reaction to the permissiveness of the Hanoveran Kings before Victoria.

(For convenience, I'm using "illicit sex" as a general term to include adultery and non-marital sex).

My real issue is as follows: Hays Code moralists (aka sex-moralists) argued that more revealing clothing encouraged illicit sex. That may be so, but different "revelations" of the female body might have different effects on the illicit sex rate. I suspect the move from one-piece swimwear to bikinis had a stronger effect than allowing the exposure of ankles and wrists. And sexual-moralists don't seem to recognize this difference of effect - for them, every change is the end of the world. Worse, they don't tend to care about the double standard (in dress and behavior) between men and women.

All of this makes me think that sexual-moralists have a vision of how the world should be, and are willing to say whatever is necessary to push the actual world in that direction. Forcefully asserting that revealing female clothing will lead to the end of civilization will cause (ceteris parabis) women to dress less revealingly. But asserting that when there's no reason to think it is true is not an empirical project.

I'm not saying feminists haven't done some similar things - politics mindkills us all, not just those who disagree with me. But that doesn't mean feminism as a whole is anti-empiricism, any more than assertions that "allowing same-sex marriage will lead to chaos" are proof that all sexual-moralists are anti-empiricism.