There's a difference between "camping" and holding a high traffic choke point. Since I assume you're talking about MW2 I'll put it this way, someone watching one of the bridges on Invasion or the the food court area or ticket area on Terminal is holding a choke point. People hold those for tactical advantage. Someone lying down in a random house on Invasion that's away from the action hoping that someone just walks by so they can get an easy kill is camping. The first I'm 100% totally fine with, it's a tactical game, hold important areas for tactical advantage. The second I think ruins the game.
How does that ruin the game? Maybe for the dude camping its probably boring but i dont see any other way.
Yeah, I've never understood the whining about camping.
I actually enjoy playing against campers even. Its fun trying to dig them out and getting the upper hand. Team campers is even better. Do the people whining about campers never play king of the hill game modes? The whole point is to camp.
I posted in the MW2 thread about using camping as a team strategy where most of the group funnels people to one or two others on the team that are in a position to easily kill them. Switch the players doing the "camping" and even position to keep the other team off guard and kill counts balanced.
Mostly, camper is just a bastardized phrase that people like to yell and blame for them getting killed and whining about it. Most campers are not very good players and so if you're good you can easily kill them. If you're on a team and someone wants to camp then instead of whining about them why don't you use it to your advantage? You can still play the game how you want to, but can also help the team, or you can accept it as a challenge and try to improve your play.
All of that being said, I prefer fast-paced hectic shooters for multi-player most of the time and camping is largely ineffective in them (actually it often makes you an easy target).