I've spoken to a few women who claim to have been traumatized by purity culture, saying they were compared to chewed bubble gum, a flower that lost all its pedals, etc.. and subsequently complaining about the double standards when it comes to purity culture. Considering that it's much easier for women to lose their virginity, it makes logical sense to be more strict on women with regards to purity culture. As long as a guy doesn't pursue a woman sexually, there is a lower risk of him losing his virginity before marriage compared to a woman since men typically are the ones to initiate sex - it takes effort on his end. A woman, on the other hand, will always have to deal with men approaching her for sex. If there is no stigma attached to female promiscuity, if she doesn't feel like her value is lessened from premarital sexual encounters, she is far more likely to eventually succumb to one of these advances and have sex - all it takes is for her to say yes which is inevitable if she will not be shamed for it afterwards. Purity culture's emphasis on female sexuality creates, more or less, a balance between the number of men and women who wait until marriage to have sex. Women do need that extra stigma because it's far easier for them to slip up than vice versa.

Note: This is not an argument in favor of purity culture. I am merely arguing that it makes sense for religions and cultures which do practice purity culture to place greater emphasis on females than males.