That's not possible unless you have a centralized, relatively single-minded society. You don't. You can't be an outcast from a land full of people doing whatever they want and making their own rules.
What people really want to do, when permitted to make up their own rules, is cooperate and specialize. They will make up the rules that makes that as efficient as they possibly can because the vast majority of individuals expect to personally thrive in that type of environment. You don't need centralization or single-mindedness to ostracize people who treat their fellow men unjustly. Each person finds it in their individual self-interest to ostracize such people.