I don't think the issue is fraternity man and possible sorority women having sex so much. But that it happened in public and just a little over two weeks after this.
The Rules According to a Fraternity "Cocksman"
When this was going around earlier (weekend and yesterday), some of the pictures I saw were not only more graphic than what is linked above, but included both of their faces full on. There was also a picture that included some of the event happening below that kind of showed the sponsoring sororities’ letters. Perhaps not a big deal to some - especially if you are not familiar with the Greek letters. But it took me maybe a few seconds to figure them out. Also, my understanding is that some of the new sites confirmed which sorority was having the event and it was worded such that the girl that was fiddling on the roof was perhaps a member of said sorority.