Since you asked …
I think the main point is a good one. That is, the general public has a poor understanding of economics. I think you could extend this other sciences as well. As he points out, this makes it easy for politicians, media and inertest groups to influence the public with inaccurate, simplistic arguments.
I do think he could have done a little better job at emphasizing this point, because the bulk of the article is the standard line you get from the Journal’s editorial page – free markets, low taxes. For example, despite the headline, he spends the first half of the article talking about free trade. When he finally gets to taxes, he reiterates the standard line that lower taxes don’t contribute to deficits, including the obligatory defense of the Regan tax cuts. Then he throws in a quick jab at price controls. Only at the end does he get back to the point about the general public’s understanding of these issues.
Overall, it’s hard to find much of anything I would disagree with.