It's a reoccurring phenomena in games, in which a tactic or particular mechanic is perceived to tip the balance of the game in the users favour by a large degree. It is then classified as unfair, and those who utilise it to be unscrupulous. What in actuality happens is that the victim of the perceived unfair device is ill equipped to counter it, which in turn causes him to lose - reinforcing the idea that it's unbalanced in his mind. The DMR is the dream-crusher of many Halo players' delusions of grandeur. They themselves have not learnt to counter, perhaps even use it, and thus perceive DMR wielders as effortlessly winning thanks to the amazing balance-tipping powers of the DMR itself. Thus, only noobs use it. "Get on my level, and win with skill, pls."