As women go, so goes society. Men do whatever is necessary to have frequent and convenient access to sex. If women require marriage, men marry. Masculine-style sexual freedom practiced by females dooms marriage, faithful husbanding, and responsible fathering as institutions.
Cheap, casual, and easy-to-get sex is available in masculine-style sexual freedom for females. It reflects adversely on all females. They appear ordinary, because nothing separates individuals from the pack. Hoping to be equal, they fail.
Modern women appear as just more of the guys. Men do not marry guys or stay with ordinary women for very long. A woman who appears ordinary stales fast in the face of erotic scenery outside the home.
On the other hand, crossed legs hold special appeal to the Marrying Man; his competitors also failed to bed her—or so he concludes without contradictory evidence. She guards her sexual virtue with dedication for the main man in her life, as he sees it. This makes her more unique than others, maybe even extraordinary, and worthy to be his wife.