this post seems incredibly dense and convoluted. I literally do not know what you're talking about

That was not my experience. I understood everything in the first five paragraphs without having to reflect or even read a second time except that I did have to reflect for a few minutes on the last sentence of paragraph four. Although I am still less confident that I know what Justin intended there than I am with the other sentences, I am 72% confident I know. I think he meant that even if we are not religious, society tends to pull us into moral realism even though of course moral realism is an illusion. (Time constraints prevent me from reading the rest now.)

Defining "supergoal uncertainty" would be a necessary step

Oh, he did that. And the definition was quite clear to me on first reading, but then I have done a lot of math, and a lot of math in which I attempt my own definitions.