There are some systems that mitigate this.
- It's boring, if you join at the start of the match you have a good while to wait until someone has looted and is ready to extract.
- You don't guarantee your loot, early extractors might just have base materials on them, nothing special
- People have secret pockets in which they'll stash the most epic loot they've found, blueprints, epics, keys. You can't loot that.
- Arc patrol heavily around extraction points and provide a constant nuisance for campers there.
- It's risky, with a high TTK even if you're ambushed you can turn around fights. There's no guarantee the person you're ambushing isn't more dangerous than you.
If you're good and you just want to ruin other peoples day, then you'll just go to where the fights are, follow the gunfire and explosions and launched flares of dead players.
If you have been killed at extraction, odds are it wasn't a camper but another person just looking to extract, a good reason why it's often a good idea to call friendly over prox chat. From their perspective they're full looted and ready to extract, they dont need what you have, they're just trying to protect their own haul.