Many people complain about campers. I personally don't have a problem with them. Even though I don't typically camp any more, I consider it a skill to find a quality spot where you can successfully camp and not be too vulnerable while still being effective.
So, please don't complain about campers. it's part of the game. Instead, here are some tips for dealing with them...
Campers are predictable. This is pretty much the main thing that you need to know in order to stop complaining about them and, instead, defeat them. Your approach toward taking out a camper is based on this issue of predictability.
Let's say a camper has found a great sit spot where they can only be attacked from one angle, they aren't very visible, they are near a populated area, and they somehow have access to some ammo/health/armor.
Here's what I do.
Usually camp spots don't allow a lot of movement. This makes them a prime target for being nexed (sniped). If, for some reason, I can't successfully nex them, then I will use a weapon with splash damage and slowly drop their health. If their health drops enough, they will at least have to get up to get health. They are vulnerable while doing that. You can possibly rush them. Or you can get you and another teammate to attack them at once.
In fact, rushing up on a camper is generally a good tactic, especially if they are using the Nex because they will be zoomed in a lot and might not see you. Come in from above. Sit on their head and shoot down.
For act two... you camp the camper. You utilize predictability again. You know that they will probably come back to this excellent camping spot. You watch the camp spot and kill them when they arrive. Do this a couple times and they will usually leave the spot alone.
Those are my thoughts on campers. There is a reason why I don't camp very often anymore. It takes way too much skill (and lucky map design) to apply camping against good players.
Many years ago, I had a friend who was awesome at finding good camping spots. It is definitely a skill.