I actually did some quick research. RPG is technically every game you play.
You play the role of a player in the game environment. Even Pong or Tetris would be considered as RPG. The ball would be the player or the shapes. But this thread is not a waste of breathe. It is allowing people to express their take on how they perceive a word to be. Like to me FPS would be a First Person Shooter and to others a camera angle titled as a game. (last I checked shooter was a genre for games) Also MMO to me is Massive Multiplayer Online and to you its MMORPG. But if it it so pointless why you keep coming back? It must strike a cord somewhere which means to you it does matter.
If something can be taken from this thread its the fact that we all have our own perspectives on how genres, titles, and their meanings are to us in this line of work. Be it logical, technical, or idealistic. As in the popular meaning.