There are always ways of enforcing norms and mores. These show up in all human societies. Even in a criminal gang, pirate crew, or savage tribe, there are rules, and breaking them will get you punished. The social contract in the US gives the state most of the power as a grant from the sovereign people. Other countries have differing rules, but the fundamental principle behind the rules is ensure justice and fairness, or at least the appearance of such.
This is especially applicable when someone is accused of a crime. Because mobs demand blood and the state is not entirely trustworthy, we weight the system in favor of the accused. Even if someone kills some poor guy in front of a police station on camera with dozens of witnesses, we give him his day in court. However, this only works if the government is willing to punish wrongdoing.
Once you lose that, well, it falls to the old rules. The lex talionis, the Law of Revenge. Hang em’ High!
Jed Cooper: You’re lynching those boys. Why?
Judge Adam Fenton: Why? Because of you, Cooper. Because of that beautiful, that magnificent journey you took to bring three killers to justice. Because if the law didn’t hang them, the next posse that goes out will say, “Hang ’em and hang ’em high, there’s no justice in Fort Grant.”
We see this happening in Britain. The law is aiming to prevent hurt feelings and political incorrectness, rather than administer justice on behalf the populace. Therefore, you turn to the old rules: