This is totally outside the scope of your specific point, but I think it is important to note that the objective "a better community" is difficult to measure. My question: is a CoC an evidence-based response? Many software communities have moved to adopt CoCs, but what are the effects? Is there selection bias in studying a community with a CoC because (by virtue of accepting the CoC) the community is more likely to reject unprofessional behavior? How do CoCs function in a global society where actions that are appropriate in one culture might be taboo in another? Who/What is the arbiter of cultural disagreements - NAP? But the understanding of violence/aggression once again falls apart in the wake of cultural differences.
Ultimately, the answers to these questions are decided by the CoC, but who are the authors and evangelizers? The contributor covenant first appeared in 2014, and rapidly (e.g. within 1 year) saw Google (for example, there were many other large tech companies) adopt it for public projects. I believe that we should consider what the motivations are for these multi-national companies to so quickly adopt these rules.