A commenter writes that when he was in a fraternity:

“… we had the “rapey” reputation on campus. But that rumor was entirely manufactured and perpetuated by other fraternities to poach rushes from us; sororities didn’t care about it one bit. And that’s pretty much what happened to the country. People heard a bunch of rumors and called it an epidemic, even though the average co-ed does not act like that is remotely true.”

I’ve heard the same thing from the other direction: “Oh, sure, my fraternity made sure to spread every terrible rumor out there about other fraternities we were competing with.”