I spent many years to admin similar comunity site, and got a lot of experince with similar events. All of them was solved in peace and to suited both.
People cannot judge by first look. Yes, this looks like harrasment but it's maybe not so bad as it looks. If you say he's guilty without any close look, it's like in middle age. This really have to be solve privately and if admins are not accessible, you can ask moderators to help somehow. She have to prove that he did harrassment and he can apologize.
However, that's is REALLY NOT OUR BUSINESS to judge. In my eyes, this is vulgar, stupid and moral-less and everyone who judge without prove may blush. And really no matter if admins can react or not. Again, it's not our business.