Don't go full Imp. These girls are not careful students of Valerie Solanas or 70's feminist writings. They aren't knowingly attempting to extinguish men. This kind of thing has been going on for a long time. Girls get obsessed by ideas about relationships and romance. As for answering the question, I find a lot of the social-based explanations here plausible. I'm sure it feels sophisticated and cosmopolitan because that's how it is depicted in media. They also seem to find the gay affect intensely amusing the way guys tend to find certain types of things funny. Valerie Solanas is not driving any of this.