So big deal with the telephone call, except showing that the dentist is concerned about his reputation.
Such concern has a value. If a doctor is concerned about his reputation among dr1 members, then there is a good chance that his new dr1 patients will have no reason to complain.
Also, such principles as "patient's health -- the only factor to consider" and "the same prices for all patients" are not obvious, at least for some percentage of doctors. There are doctors who openly declare doctor's business interests as a factor they are 'forced' to take into consideration and there are doctors who openly admit that they charge patients with respect to patients' ability to pay.