I feel like you don't understand this game.
Let's say we're playing on Quarry. I'm patrolling the network of buildings that overlook Bravo/Alpha, when I see a red dot on my radar indicating that someone is coming down the chute. I see the skull, which means he's still alive. I run to the hallway, go prone, pull out my akimbo G18s, and aim down the hall that overlooks Bravo. Sure enough, about 20 seconds later, there he comes. I'm sure he was raging about campers, but in reality, he was forced to give away his position and got out maneuvered.
This sort of thing happens with me all the time. If I see a blip, or if my teammates call out someone's position, you better believe I'm going to watch that doorway and react before they can stop me.
Now, do some people spend the entire game camping in corners, never moving? Sure they do. And they usually go 5-3. Big deal.