I think zahavasdad made a great point. No matter how low the percentage is (we hope very), we still must do our utmost to find any perpetrator, and do whatever it takes to stop him.
I think his analogy is terrific for another reason as well. Just as something untzniusdik would draw much more attention in a library of seforim than in a secular library (which has considerably more), so does such horrible behavior stick out much more in the Torah world than in the broader society.