Camping is the most overused phrase in COD. It had meaning up until Black Ops 1 but ever since it's become a crutch for the COD community. The people who complain about it are more annoying that the camping itself. It's also a subjective term because just because when someone killed you they were in a building, window or maybe even corner doesn't always mean they were literally waiting for you the entire game.
Also I've been told my gun is OP or I'm a "tryhard" aka the most pathetic phrase COD community came up with when I rush. So people will find something to complain about. So if we're speaking about people literally sitting in one spot all game(not including snipers) then yes these people are annoying however the past 2 COD games have done a good job of having multiple flank routes so it's not too hard to get people out of their camp spots.
I actually didn't mind campers in BO2 especially because with a silenced SMG(I know overpowered right) I could get in the enemy spawn and get 3-5 quick kills around their flag or grab their tags in Kill Confirmed and the next thing you know there is an Oribital VSAT up or even an Escort Drone destroying them.
If I met them in real life, I wouldn't do anything to them. It's a video game and the majority of campers are bad players. Actually majority of "rushers" are just guys moving around the map with no awareness, vision or reflexes giving campers kills...
People are willing to use homophobic slurs and racial slurs on PSN and XBL but want to take some moral stance against camping? I'd suggest partying up or playing Cranked.