The article criticizes how economics textbooks talk about externalities, which are costs or benefits affecting people who didn't cause them. The current textbooks don't consider all the perspectives and only focus on negative impacts, like pollution, ignoring positive outcomes too. They often miss the idea that sometimes market forces can solve problems naturally without government interference. By mainly teaching one side of the theory, students might not question certain policies suggested as solutions. The researchers argue that this one-sided approach can be harmful because it doesn't prepare students to evaluate all possible solutions to problems caused by externalities, which could potentially hurt society in the long run.