I see this argument all the time, especially on Reddit: “you don’t understand economics” or “clearly this person doesn’t understand economics.” Whenever anyone says this, they don’t actually attempt to explain what it is the person doesn’t understand, or even how their argument is wrong, or even engage with what’s being said in any way at all. It’s just tossed out there like a mic drop. “You just don’t understand economics” is the ultimate thought-stopping technique deployed whenever anyone questions conventional free market orthodoxy. The subtext is that anyone who has any opinion outside of the narrow box of laissez-faire capitalism is a foolish, starry-eyed dreamer, whereas the hard, grounded poster “gets it.” But, of course, the only thing they really “get” is the economic doctrines they’ve been spoon fed their whole life.
This lecture by Ha-Joon Chang is a good refutation of the non-argument “you just don’t understand economics.”