That's the point. Most people in toribash are derisive, and something that is short and easy to type, yet gets a lot of emotional response, will become desired. Rip is basically a quick, ironical outburst when all is lost, just to piss off the loser, just like the "easy save" comments. People love irony, and "resting in peace" is just a nice ironical icing on the cake that gets jammed in a loser's face. The whole point of the game is to keep your cool, and if you can get knocked so off-base by 3 letters, they're succeeding in getting under your skin.