Can you force a player to **Bang** themselves when Dorothy Rage is in play?
From a post by the designer of Bang!, Emiliano Sciarra:


  ... you cannot play Bang! on yourself ...


Also, this official ruling from the FAQ for the Wild West Show expansion


  The action you describe must be possible for the player


By combination of these two rulings, Dorothy Rage cannot force a player to play a self-targeting "Bang!".