* Don't be a creep or stalker * Don't tell sexist / racist jokes * Don't tell a trans man he's really a woman, or a trans woman she's really a man * Be a grown up * No, seriously
which seems pretty reasonable.
The arguments against a conference having a code of conduct aren't really that different from the arguments against the Constitution having a Bill of Rights back in the day, and now in these latter days I think we can see how that all worked out.