You heard me. Noob weapons don't exist. You aren't a noob for using shotties or fusion rifles or Thorn or SUROS or Vex or anything in the Crucible.
These guns exist in the game, and therefore, it is fair to use them. Maybe fusion rifles are the most effective all-round guns in the Crucible, and maybe it pisses you off when someone uses one for the entire game without ever switching to their primary, but that doesn't make them a noob. The only noobs are people who deliberately handicap themselves by using sub-par weapons because they are somehow 'fair'.
Consider a few comparisons. If someone brought a green rocket launcher into a Raid, when they have a maxed Gjallarhorn sitting in their vault, you would call them an idiot. Similarly, imagine there was this incredible weapon; an LMG with infinite ammo that shoots Gjallarhorn rockets. Obviously this would be the best gun in the game, and very overpowered. But you wouldn't be a noob if you used it. In fact, you would be stupid to use anything else, when this gun was clearly so much better.
What I'm trying to say is that you can complain about game balance, and maybe you complaint will be legitimate, but you should never call someone a noob because they use the best guns. I also get frustrated when someone constantly one-shots me across a room with a shottie, but ultimately they have every right to do so, and they aren't a noob because of it.