Because why not?
The game is simple: You post a message wherein you supposedly "ban" the person right above you for silly reasons. An example:
Guy A with an Olimar pfp opens the thread
Guy B replies: "Banned for having a Pikmin profile picture."
Guy C replies: "Banned for replying to this post."
Guy D replies: "Banned for making metafictional jokes."
The reasons can (and should! :P) be as stupid, surreal, meta, or utterly nonsensical as you want. Just don't go too far or do anything offensive. I'll be watching.
Go ahead, you chums. Ban me! Start the game!