If someone chooses to go rogue they have some penalties while also get some loot from the remaining scavs they kill. If someone chooses to be a good scav, they occasionally get rewards from fence if they extract with other pmcs and can get to high rep with him and buy extra stuff. It's just a different playstyle, stop acting like it's the most disgusting and disrespectful behaviour in the game or some shit.
Just stop being salty for losing shit loot because someone didn't wiggle back. It's a hard and punishing game you're all after either way right? If you guys spent half the energy you waste crying about scavs killing you and focused it on bears and usecs killing each other I think the game would be way better.
Also: "They gather into packs, living by dog-eat-dog rules, cutting each other throats over a better piece. This is how yesterday's civilians become Scavs.". That's the official description for scavs. It's meant to be like that.