[Lalo-ATX]

I think Kahneman's Thinking, Fast and Slow can add a useful perspective.

In the Kahneman hypothesis, humans are naturally parsimonious with our mental energy, preferring to use System 1. If we are writing a good essay, we are investing real System 2 effort. When we read someone else's writing, we get a free ride.

Difficulty and (lack of) motivation in your schema drives people towards System 1.

I agree that "obtuseness" is too reductive. There are copious examples of people who have had brilliant insights through the application of their System 2, who go on to embarrass themselves with shoddy System 1 thinking. Anyone can be obtuse - or not - it's just not a clear category.