Interesting web address for someone trying to defend the system...
I have issues with the assertions in the article.
High school students aren't going to be taught by professors for the most part. They're taught by people who have a bachelor's or master's degree, and underwent certifications. Either way, they're not being taught by other high school students, unless it's in a peer tutoring session. Even then, the tutoring session will be conducted by a student who is significantly more advanced than the one being tutored.
The teachers of a high school are still going to have a significantly greater degree of mastery of the subject being taught, than your average high school student, assuming that you don't have some amazing prodigy on your hands as a teacher. After all, we can't all have dojo's stocked full of Jigoro Kano types...
I agree that much of the teaching is dependent on its presentation. After all, serving someone a perfectly cooked filet mignon steak on a dirty ash tray is probably not too productive. However, the instructor at hand must still have at least a decent modicum of knowledge, or else it simply becomes an enthusiastic person teaching poor techniques. If anything, I frown upon such "instructors," since their students are more likely to get hurt in some way shape or form.
In that case, you end up developing students who have awful fundamentals, and having them unlearn such fundamentals takes a lot of time...