When we look back at the '60s and '70s sexual, racial and cultural revolutions, there are clear unintended consequences that no one brought up then. One I like to mention is how women demanded the same sexual license as men for fairness. They asked to be given the same runaround freedom. If it was about fairness, why didn't they just say, "We will shame men who are male sluts and we will hold men to the standard that women face now with shaming techniques"? This probably would have benefited society as a whole. Go ahead and bitch all you want about a society that would limit your sex life, but you'd have a nation of low notch count or virgin women to marry. The choice to have women sink to men's standards, and then men sunk lower, and then women caught up, etc. was because ugly feminists needed to use their new weapon (the pill) for getting better mates.
Everyone had that female friend in college who was prettier than her wingwoman but would not pull the guy in at the end of the night she wanted and she'd wonder why, but you wouldn't say "You're friend is easier". Signaling openness is a way to draw men in, as guys will go for the easier choice because they fear rejection (or they just have low standards). While anecdotal, there are studies that back up the idea that prettier women have less casual sex. Pretty girls don't have to do as much of anything as ugly chicks to get men's attention, money or good treatment. They have what men value: attractiveness. In 1968, it would have been easy for the feminists to demand men be shamed or held to the same standard as women were, but there was a selfish motivation to this. Ugly chicks now had the pill and could have consequence free sex to rope men in.
The pill gave ugly chicks that nuclear option for evening the score. Review fiction forever and you will find the plain types 'settling' for older men, ugly men, fatties, bald men, or ending up spinsters. They didn't have the looks to get the guy. The pill disrupted the sorting of approximate attractiveness or money + male attractiveness = female attractiveness balance of society. The pill gave uglier women baby free sex to use as a weapon against prettier girls in the mating market. "My pretty friend is a bit standoff-ish, but I'll fuck your brains out tonight" is a phrase to lure in a buzzed or drunk handsome guy. Men are easy to persuade, and often take the easy way out.
Hardline feminists that would be movement leaders, who usually are uglier than the average lady, would need the lower standards of behavior. Even if they had the pill to prevent pregnancy, there would still be the shame of being easy. What good would the weapon of sex be in the mating world if guys still considered a chick who banged over 3 men as a skank (my dad's view in the '70s). They had the tool. They just needed to shape the environment. Destroy standards of sluttiness. There is also a flip side to this, which reveals women's nature. They love a guy who is known as a slut himself. It's preselection, the stamp of approval, the sign he is a worthy catch. They needed a man to be free to display his sexual prowess so they could tell which one to go after. I'm sure in 1970, those feminists saw the wonderful world of illegitimacy, hyper-sexualized children, broken homes and widespread herpes + HPV infections that they were creating. They couldn't have been that self centered and narcissistic.