Because the Hippocratic oaths are reserved for doctors of medicine/osteopathy , not for psychologists. Psychiatrists are doctors of medicine, psychologists are not
Just need to add Osteopathy believe that the Subluxation is the cause of disease, just like Chiroprators.
(Modern Osteopathy Schools are basically medical schools, usually for people who didn't get a spot in a med school. Are they as prestigious, or fancy--no, but the graduate can prescribe, and do surgery.)
Yes, that is the point.