Actually, I'm not even sure that "enforcement" is all that relevant. It's more about articulating the norms of behavior so that people can learn from them and grow.
Bingo. Furthermore, any of the stuff in the CoC seems pretty reasonable - don't express prejudice, don't harass people. It's really "Social Graces 101" level stuff, not some bid to constrain free speech.
Unfortunately a small minority apparently don't know how to behave appropriately around others, and need this shit to be spelled out.
Obviously, 99% of people are not going to make prejudiced jokes or comments in their presentation or in groups at a conference.
A code of conduct simply sets out the expectations at this level, and creates a standardized procedure for what to expect when these expectations are violated.