Yes, a Code of Conduct can be a good thing. A good CoC is about the outcome, not the action. For instance, a good CoC in software development has things like:

* Write your code for other people who may be up at 3am trying to figure out what's wrong with the logic.

* Be considerate of other ideas, smart people who disagree are usually both correct but differ in benefits and consequences.

* Consider if you are writing beyond the scope of the ticket, no code is easier/faster to debug/understand than no code.

Notice, there are no rules of what to do, but what is attempting to be avoided. Unfortunately, the Western Thinking (TM) (as opposed to Eastern Thinking) asks the question "What is...?" Like:

* What is the correct way to address someone?

* What is the acceptable code style?

* What are the maximum number of lines in a function?

The problem with this thinking is that it ignores outcome and enforces concrete thinking. The irony here being that the goal is to be considerate of people and they are being utterly inconsiderate to the moderator.