There's something sort of adorable about people who have a Hazlitt-level understanding of economics and assume that there's nothing left for them to learn. It's like a puppy with a habit of stealing your mittens: Cute for a while, but eventually it becomes irritating.
No one "understands" economics. I almost have my PhD in it, and I certainly don't "understand" it. People with Bachelors in econ don't "understand" it. People who've taken a couple courses certainly don't understand it. Economics is fickle, counterintuitive, caveat-riddled, vast, amorphous, and often inscrutable. Trying to understand economics is a hopelessly Sisyphean endeavor; anyone who says otherwise is selling something.