I think everyone else has addressed most things and I agree.
But can we talk about your workplace culture?
How the FUCK did this spread? This should have been a personal thing between your friend and HR.
Well from what I've seen in these situations, people are usually unsure of what to do about something that makes them feel uncomfortable. Most will not go straight to their boss or HR because that means causing trouble. A new employee in particular falls into this category. Instead people start by confiding in a co-worker, or co-workers, about the situation. More than likely whoever she talked to recommended that she go to HR, and said co-worker(s) spread the story from there.
Keeping in mind that it's completely possible that OP's friend may have been seen behaving like this before, so people are more willing to talk behind his back.