They have ALWAYS been this way, especially the men on the left. Don't be under the mistaken impression that self-styled "progressives" are less sexist than those on the right. They are often much worse. I can tell the author was not around or too young to remember the 1960s and 1970s, when sexual liberation became all the rage. It has nothing to do with women's rights; in fact, it is completely antithetical to women's rights because sexual liberation is all about greater and easier sexual access to women by men without any consequence for their actions. It is about supporting the violation of human rights and human dignity as these "progressives" worship porn and prostitution. What is old is new again. "Progressives," back in the day when they were called "the new left," have always been worse about women's rights than those on the right because their sexism is way more subtle.
Porn got mainstream when you had outfits like the "liberal" ACLU and their idiot judges calling it "free speech," or "protected speech," which it is nothing of the kind. I suspect more than a few of those stupid judges consumed it on the sly.