The author admits that this article applies to only a specific flavor of music theory, and says that it only covers a small part of it. The article even mentions at the end it does not cover some of the topics you think are missing.
The article is not a comprehensive syllabus of all elementary music theory, and it does not claim to be. I believe you are being too harsh, as this approach to understanding music feels much more intuitive to some (like the author, and myself), compared to traditional music education.
The article is not a comprehensive syllabus of all elementary music theory, and it does not claim to be. I believe you are being too harsh, as this approach to understanding music feels much more intuitive to some (like the author, and myself), compared to traditional music education.