I don't see any threads disappearing other than the stupid ones that have overly sexual (you've seen the posts) or slanderous content (Coach So-and-so is drunk all of the time and has a drug problem and cheats on his wife...). You're just posting this garbage or you are paranoid.
It was the original thread about Tahoe Prep Hockey, a bottom rung prep school 2,000 miles away. It was an open thread and a few people laughed it off. Next thing the thread is locked and the original thread responses are gone.
Not a big deal, just curious why? Perhaps the Admin is selling advertising and does not want to encourage a discussion on this discussion board. Only in America!