Are the standards for whether something “sounds bad” based on the average person’s reading or the intended audience.
In its most general form (how the median article sounds to the median person), the argument is pretty vacuous.
Most writing discusses simple ideas and they should sound good (familiar, easy, pleasurable) to the median person.
But the most valuable kind of writing could sound tedious and filled with incomprehensible terminology to the median person but concise and interesting to the intended audience.
The current way the idea is stated doesn’t sound correct because you can convincingly defend all 4 quadrants of the truth table.
As pg describes it in the article, it's neither; it's based on the writer's judgment. The writer of course is writing for some intended audience, and their judgment of what sounds good or sounds bad should be influenced by that. But pg is describing the writer's process of judging what they write.
Related: I think pg would benefit from graphics here and there. Creating visuals like the 2x2 matrix you describe help tremendously to make ideas more comprehensible.