I've long
thought about the reason hippy woman became so horny and available for
sex, for the fifteen years from 1965 to 1980. I've believed that it had to do with demographics. (Women of the
relevant age cohorts outnumbered the men by nearly two to one.)
I now think that was not the reason.
In the 1990s after the fall of the Iron Curtain, I saw what happened to women. In Eastern Europe and the former Soviet Union when the yoke of Lefty tyranny fell, woman swarmed all over Europe, Japan and the rest of the world offering sex for sale. Sex was also free and abundant to nearly any visiting man in the former Soviet zone.
I saw hippy female sex behavior in E. Europe, without any hippy values.
Now I think the hippy world saw their (our) world as a radical birth of freedom, a wild escape from the straight-jacketed hypocrisy of the 1950s. I now see a parallel in the hippy sexual liberation to what happened with the fall of the USSR.
Sexual abandon comes from real and perceived freedom not from demographics.