There are campers and spawn campers. Two different things. Campers are people who just hide around corners somewhere and wait for people to come into view so they can kill them easily. It’s all about response times. A camper only needs to process the player coming into view while the player turning the corner has to process the new environment as well as the player laying in wait. This tends to give the camper an edge. It is considered by many to be a somewhat cheap tactic and is often used by players of lesser skill (though skilled players will also use it for the advantage it gives). Often you need to flank campers or flush them out with grenades (if not outright kill them with the grenades if they are foolish enough not to move).
Spawn camping on the other hand is waiting near the enemy spawn for the enemy player to respawn and kill them before they have a chance to process their environment and respond. It is considered an extremely cheap tactic. I don’t know why so many games allow this at all. There should always be mechanics in place to prevent this sort of thing. If the game mechanics allow for spawn camping there really isn’t anything you can do to counter it which is why it is seen as being cheap/unfair to the degree that it is.
