That’s true, and if you had simply expressed your lack of understanding that would be perfectly reasonable, but “probably not very [productive]” is a judgement,

That’s true, and if you had simply expressed your lack of understanding that would be perfectly reasonable, but “probably not very [productive]” is a judgement, is what you wrote, and what I pointed out was a bad take. Edit: The edited and expanded comment (initially, it was just the single first sentence) directly contradicts the first sentence: subjective opinions on form factors don’t lend to definitive statements about productivity.