This is a bit absurd. There needs to be a way to rout enemies and force them to regroup. Being able to respawn to constantly continue fighting is not very balanced. It allows players to instantly respawn on top of enemy forces with no recovery time for infinite waves.
A) Prevent PvP players from using camps.
B) Make camps PvP flagged or not - PvP players then can only used PvP camps. Allow PvP camps to be destroyed by PvP flagged players.
C) Make areas around PvP objectives landmarks, with a fair amount of distance to prevent camps from being placed near objectives.
D) Have a respawn timer of 30 seconds or so to respawn at a camp while PvP flagged. No time for respawning at a settlement.
Personally, I’d like option B. At least let us destroy camps. Probably requires a lot more coding effort than A or C, though.