In a way, I think coercion is a requirement to be ethical. Ethics is determined based on what current society believes to be the right thing to do. We see that there are a variety of different cultures and ethics around the world, which would indicate that humans wouldn't just automatically follow a universal set of rules.

Thus to be ethical in your society, usually means you must follow the rules determined by a collective group of your nations ancestors or you will be shunned/jailed/harmed/etc. Which is essentially coercion. "Act this way or be punished."