Have you signed any contracts at all in your life? The protections and restrictions from that contract are enforced by the same mechanism, via the same social contract.

Did you sign anything agreeing to not murder?

I didn't realize we were suppose to sign social contracts, must've missed that memo.

Honestly, if you don't know what terms like "social contract" mean, you should go read what it is, not just antagonize the person who's sharing an educated opinion with you.