@verius I think you're very biased about what a code of conduct is. It's like you have some preset that can't be argued with.

Rules of engagement when it comes to groups of people are always beneficial. Whether they need to be written down or not depends on how diverse and/or tight each respective group of people is. Larger groups (think organisations etc.) definitely need a common baseline of conduct. If there are people in the group who can't accept that,(or the rules, assuming they're democratically decided) I guess they'll have to find somewhere else. There's no universal human right to hang out with people who don't like your behaviour.