I don't play Warzone, it requires a skill set that I don't really have so I don't class myself as an expert, but I would like to share my take on this topic.
First, camping in Warzone, unless you are lucky enough to setup camp in a spot that ends up in the final circle, then camping will get you killed, so you can't camp in one place for too long.
Watching videos of good teams playing, what I see if that they will get to a point in the map and plunder all the loot boxes they can find so that later in the game they can buy back team mates, loadout drops and revives etc... so camping means you will miss out on the loot. However, posting a sniper in a nest above your position means you have an eye on the terrain while the rest of the squad plunders to get funds for use in the stores.
If a sniper shoots and gives his position away to then stay put then they are just asking for an RPG in the face and Carlos is happy to oblige, so they need to be mobile enough to avoid that.
Sniping from a nest is part of a strategy, the chances are if you see a sniper then the rest of the squad is nearby, so adapt your approach to different locations,, maybe if you identify where the likely nests will be then you can RPG the nests as a pre-emptive strike and if you get lucky you have 1 less hostile to deal with as you get closer to your next goal.