I havent noticed much noob behavior of the gunners just behavior fitting its power. I HAVE seen noobs on the other end of the gun, running into the open, not taking cover, TRY to hit me as I pour countless rounds down in their direction from my autorifleman.
The gun has a significant settle time for when you are in deployed mode. It takes 8 seconds to become 100% accurate. Less if youre closer than max distance, but still, I see one of two situations:
A. someone is running around in deployed mode to be ready to drop and provide cover. This is what I do. I tag along just behind my squad and have it ready to drop and provide heavy support. Sure I cant take out guys accurately without scoping in and waiting, but I let my riflemen do that...
B. They run around undeployed and then waste you at point blank or have to deploy to hit distant targets. Well, this makes sense too. Come around a corner, both spraying and praying and its bound to be the guy getting most rounds downrange that gets the kill

If youre far away, they have to stop, deploy, and settle before engaging givingf you the advantage.
My advice is play with the kit for a few rounds and see how it works if you havent. Then, once you see how its effective, think of ways to avoid attacking it head on. If its deployed and waiting for you, you shouldnt and WONT stand a good chance of taking it out unless you flank or something...
Its one of the most feared weapons in real life and in PR, which makes sense seeing as its basically a heavier rifle that shoots rounds much faster
If they get the drop on you, pull back, flank, or conceal with smoke. Dont go in head on, you WILL die.
You say they are begin used for the sake of it, not when they are needed... well, Id beg to differ and say they are ALWAYS needed which is why they are ALWAYS issued in real life to small groups of soldiers
