I think the value of a CoC is merely to signal to people who have experienced abuse or disrespect in communities before (which would describe, I think, most women and people of color who have participated in technical communities for more than a short time) that the community is on their side when sexists or racists show up. That has some value. It doesn't really matter to the majority, and it doesn't actually alter how people behave (generally), nor does it really alter a project leaders ability to excise a toxic person. But, it does say, "We will excise toxic people. We will try to make you feel welcome here, even if you have been made to feel unwelcome elsewhere."<p>Even if that's all it does (which I think it probably is), it is enough to make it worth doing in most cases. (Which reminds me that I don't have a code of conduct on any of the open source projects or communities I work on, but I'll make it a project for the first quarter of this year.)