Valve says: “We shipped it by mistake, as it wasn’t something we wanted to be a part of the game. We haven’t built the game around having it in, and it just stops it from working,” explains Walker. Breaking both the Spy and the Pyro, the TF2 team decided that friendly fire prevented the game from being any fun to play, and it will soon be gone completely."

Obviously they haven't played as a spy on normal servers... This is sad news, those of us who actually like having to think or aim before we shoot, can now just spam like the masses without consequence.