And yet this entire subthread is about a proposal to create a social network "designed from the ground up to be a public square for civic discussion between people who disagree" that has "mechanisms to agree on facts, and tools to create arguments supported by those facts".

Isn't HN supposed to be a place for civil discussion between people who disagree?

If you write off arguments you disagree with as "tiresome" and "beating a dead horse", especially on something as basic as "what is evidence", then you're providing a strong negative counterpoint to the original proposal - do people even want a place where people can agree on facts and then disagree on the results of interpretations of those facts? Or do they want, as you seem to want, to retreat into their comfortable social network of people who all agree on the same unwritten body of pseudo-facts?

Equally tiresome political issues are on here all the time. There are also fairly regular (and equally redundant) back-and-forths about programming languages.