Reports ARE associating the content with the user of the app. There is no privacy on it. Users are creating an event and putting the reported id on it. 

Reports ARE NEVER PRIVATE. The name "report" should already tell you that.

Mutes are private on Amethyst, but other clients make those public as well. 

They are all associating the user with the bad content. There is no way to do any of this without that association.