I don’t think that Duncan tried to describe what everyone has agreed to, I think he tried to describe the ideal truth-seeking discussion norms, irrespective of this site’s current discussion norms.
Added: I guess one can see here what the algorithm he aimed to run, which had elements of both:
In other words, the guidelines are descriptive of good discourse that already exists; here I am attempting to convert them into prescriptions, with some wiggle room and some caveats.
I don’t think that Duncan tried to describe what everyone has agreed to, I think he tried to describe the ideal truth-seeking discussion norms, irrespective of this site’s current discussion norms.
Added: I guess one can see here what the algorithm he aimed to run, which had elements of both: