These threads that you are referring to do not need explanations for disappearing. Most of them are spam threads or multiple posts. There are more then one ways to remove a thread. Sometimes you get the oops message sometimes you dont. End result is the same.

I dont see why you think mods need to be ashamed of anything they are doing their jobs. Inspite of giving reasons endless times people still repeat the same stupid postings or keep doing the same mistakes. Hope you understand now.