The veteran cynic in me asks who benefits from this action. After all, the behavior that the code of conduct seeks to get on top of is unacceptable in any environment anyway. Yon don't change bad organizational culture with paperwork, you do it with enforcement of standards.
The first step is to establish a shared understanding of what is acceptable (i.e. code of conduct). Without that code of conduct, there's nothing to enforce.
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.
Articulating the norms of behavior? The norms in this code are the basic skills of interacting in society, anyone past the age of 17 should have internalized them. More: one expects anyone past that age of live by them, and consequently one can (and should!) deal with any violator in the appropiate manner.
This is one way of enforcing these standards. Think of them as "interfaces" that everyone is exposed to and encourage to implement. It's up to you to go along with them or not, but for the benefit, sake, and sanity of your team members, it is recommended that you stick to them. If one doesn't and things start to get buggy or not compatible, then other would ask you why you didn't follow the implementation.
It is unfortunately that something like this has to be implemented because it is common sense, but if PyCon or any other organization has to be policing their attendees like children until the learn, then so be it.