I think a better label would be "whole class of player that will do whatever it takes to win."
On paper, it sounds reasonable and beyond reproach. Hell, it sounds like the most rational behavior, right?
But in the context of the actual game, it blows. But let's be honest: it boils down to "they don't play the game the way I want them to." It's difficult to blame them, though; I blame the devs for allowing their game to be played to such great success with knives, dual shotties, and the like.
Silly us for expecting this to be a game about guns. Instead, it's a game where 50% of the players pick a spot and sit there for 10 minutes and pick off any poor bastard to wonders by, or worse, run around with their heads cut off whilst stabbing people from 10 yards out.
I completely agree with what you've written here.
I suppose on a competition level, doing what it takes to win, within the limits of stated rules (i.e. not exploiting a glitch) is what you should do.
But on a "fun" level, playing the game takes away a lot of fun because to level the playing field everyone has to play like that and it takes something that could be tactical and suspenseful into a bore fest at best and a frustrating waste of time more often.
While campers are annoying, they don't bother me nearly as much as the people running around with dual shotties with lightweight and marathon and commando.
To keep so many different weapons and styles "balanced" the developers made it unbalanced. For instance, the "knifers" can rest assured that if you have an assault rifle and they run quickly right at you and get close enough (which isn't that close) to commando knife you, it doesn't matter if you get a few shots in becasue it doesn't kill them. A larger penalty, say, the immediate halt of "running" or inability to draw a knife or change weapons, might help.
Any dual shotgun is insane. I picked up an akimbo 1887 off a dead guy just to see what it was like. I felt dirty using it. I killed a guy on quarry from a distance, hiding behind a block, with a two finger trigger pull as he was shooting at me. I saw why so many people did it. It doesn't make it right though.