Instructors are a reflection of their instructors; they do as they have seen their instructor or fellow instructors do. As a general rule, bad instructors breed bad instructors and good instructors breed good instructors.
The organization I belong to has an instructor training program of sorts but the only thing that really insures any teaching standards is the required instructor certification seminar; but it is only held for a few hours every 3 years. As a result, for the most part, instructors are self-taught; they learn though experience.Experience come from doing something for a long time. Therefore, the younger the person is, the less the experience and the less capability as an instructor.
Overall, the quality of martial art instructor training has been shaky for decades. When a school starts up, the owner teaches all day every day. After a few years of nonstop teaching, school owners want a break so they began cultivating instructors. Adult students already have their own professions, and for those who enjoy teaching, they usually do not have the time to commit to it. This means that many instructors tend to be teenagers. This is a problem since teenagers are immature and inexperienced.