The statement is misleading and more similar to the classical question of "have you stopped beating your wife ?' to which you'd be damned for either a yes or a no as your answer.

The medical syllabii have some subjects which are not purely medicine in nature.They have for example, a little bit of physics, a little bit of chemistry, bio chemistry etc., for which the persons who are more competent to teach are those who have a post graduate / doctorate in the relevant subject. Even pharmacy is a separate subject and there are people who are experts in pharmacy, who would be able to more justice to the job of teaching the subject than those who know medicine.

In fact it would be a very poor policy if one has to use medical doctors to teach physics and bio chemistry to doctors, when the services of doctors can be used to teach the subject of their profession viz., medicine.

It is not a question of whether non doctors are teaching doctors or not, it is a question of who is teaching what - a doctor teaching physics or a M.Sc Physics teaching physics.