Thanks for the response. Yes, I think some clarity about the purpose of the issue tracker would help someone unfamiliar with the project's maintenance better understand the conduct of the maintainers. If it is only for coordination of work tasks and not discussion of whether the work should be done, it would seem natural to have somewhere else where the discussion of the merits occurs.
> drive-by negativity by non-code-contributor users is the biggest existential threat
I do believe this, and it's what I was getting at with my "conditions a knee-jerk asshole response" comment. From the outside, I saw someone who wasn't being negative, but just seemed to have unaddressed concerns about the impact of the change. You, however, have been conditioned by hostile users over your many years of work to interpret this as negativity, because other, ruder people pile on to the valid concern in unhelpful ways, or the person with the concern wasn't willing to listen at all and just used a veneer of calm rationality to be a stick in the mud.
The point is, I get why you would be this way, but also that it doesn't look very good from the outside looking in. I know that you are doing unpaid labor and so nothing is owed, but still, both can be true.
I know some people don't like it, but I've always found discussions that are locked to collaborators only to be totally understandable for this reason. If you find yourself making "I know more about x than you ever will" comments to a person, you should probably instead just disregard them and carry on. Likewise, you do know more about x than I ever will, so you should probably just disregard me and carry on.