If you read between the lines, you'll know these sites are indeed beneficial. In a makeup world where they didn't exist, hacking could be thought to be done only by the knowledgeable, and not every 15 year old with a bad case of acne and pokemon posters in the bedroom.
However, it would also be much harder to fix the exploit, because information wasn't simply available anywhere on how someone might got into the website.
Handling security is not an issue of hiding possible exploits from the public in general. It is about fixing those holes and coding defensively. You'll be more secure if you know what makes you insecure, agreed?