> I don't recall any of the projects I worked on having a CoC [...] I did see aggressive list moderation be abused
Right, no CoC, just random moderators who abused their power. I don't see how that's a good thing. I think having a CoC can limit the explicit powers given to moderators so that moderators can only moderate very bad behavior like X, Y, and Z, but not A, B, and C. Of course, this depends on moderators being held to the CoC (i.e. if a moderator doesn't follow the CoC, you make it clear that's not OK so they aren't "abusive" again), and it depends on X, Y, and Z being very carefully deliberated.
> You talk about a "mass exodus". I find myself skeptical of this claim
Visit Twitter and look at Node's "thought leaders". I'll update this post with some links to tweets in a couple minutes.
> If the NodeJS contributors are so dependent on a CoC then it seems like they went badly wrong somewhere. Somehow other projects thrive without one.
Right, many projects of Node's size thrive without any CoC, they just have moderators following whatever rules the mods deem fit, or they just allow toxicity. If you want to remove toxicity while holding mods accountable, some sort of CoC is the way to go.