Yoga teachers?

A person who can teach a "good yoga class" with some "good or correct techniques" on asana, pranayama, chanting and meditation practice, who knows about anatomy and physiology about this physical body, it doesn't make him/her a yoga teacher if he/her doesn't know what is chastity or morality in his/her personal life. A person who leads a life of purity in thoughts, actions and speech, who is free from lustful desires, can guide other people to live a life of purity in thoughts, actions and speech, and be free from lustful desires, is not different from a yoga teacher, even though he/she cannot or doesn't teach other people to do asana, pranayama, chanting or meditation practice, and doesn't know anything about anatomy and physiology about this physical body...