"Raping, pillaging, and murdering" is never "justified", period, end of story.

If and only if there exists a social contract.

Without it, man exists in state of perpetual war where anything goes.

They very idea of a "social contract" is a model that implies a state with authority over its citizens. Somehow, I don't think people automatically regress to "perpetual war" without the existence of a state.

And using words like "justified" to describe regressive, destructive behavior is utter nonsense.

I fail to see how rewarding raping, pillaging, and murdering will rationally lead to less of these things.