You:> Codes of conduct are not silliness. Almost everywhere that I have seen them implemented, I have seen a better atmosphere over that community.
This implies that you have examples from personal experience readily at hand.
He then said this:
Him:> I'm curious, could you give a concrete example of a thing that a CoC has improved without simultaneously causing implicit pressure on people to remain silent about bad ideas in a project?
You characterize this as:
You:> The sealioning is because you are requesting me to provide you with an extensive example that will satisfy your stringent needs and seem unwilling to do your own research. A more charitable approach would be to go and try to find examples on your own, explain what you looked for, and could not find. Instead, you are (in your eyes very politely) asking me to catalogue a comprehensive example that satisfies all of your bullet points to the letter.
What would be an acceptable way to you for someone to ask for you to share one of your examples?