He explicitly specified that the predicted increase of radiative forcing due to solar activity in his hypothetical would equal the predicted increase of radiative forcing due to greenhouse gases in the real world.

Sure, there is still a difference between the two situations akin to that described in the Diseased Thinking post I linked upthread, in that shaming people into not emitting as much CO2 might in principle work whereas shaming the Sun into not shining as much cannot possibly work (though Moldbug still has a point as the cost-effectiveness of the former is probably orders of magnitude less than most people would guess). I know you can't shame a saber-toothed tiger into not charging you either, but still Moldbug's example worked for me and Lyman's didn't for whatever reason.

EDIT: Might be because I'd think of an increase in the solar constant in Far Mode but I'd think of a saber-toothed tiger in Near Mode.