Proper link (I think): https://haveibeenpwned.com/PwnedWebsites#Gravatar

No way to edit URL or delete when this happens?

The contact link at the bottom of HN has worked for me in the past. I also believe that the "flag" link can be used to report problems with the submission.

(The URL should be https://haveibeenpwned.com/PwnedWebsites#Gravatar )