Maybe this is true in whatever lobbies you're playing in but in higher level lobbies, such as the kind people in the flawless pool are playing in, you're gonna get punished for crutching special weapons. People who don't pull out their primaries get their rears handed to them on a silver platter, because all special weapons, while being able to one shot, only do so under their optimal conditions. Limited by range or the need for incredible precision in the case of snipers. Of course, it's easier to abuse them in lower level lobbies, because most people aren't particularly practiced in the methods to counter them.