Most oral contraceptives sometimes act as an abortifacient. This is not just a matter of Catholic Church discipline, but of natural law.
There are natural physical consequences to ingesting birth control pills. I wonder if they warn women.
That is the only reason I would see for the pills to be available only through a doctor’s cut of the action.
Since many secular doctors beleive the worst thing that could happen to a young woman is the birth of a baby, I would guess they do not tell women about the downside to birth control and the physical, mental and public mental health (social diseases) of sexual permiscuity.
Under natural law, man has free will and also, within Western ethical medicine, doctors have the duty to be honest with man in documenting the consequences and warning their patients and the pulbic at large so they are not ignorant as they make choices in life.