Strictly speaking, that's not true:
https://www.usatoday.com/story/tech/news/2018/03/01/doctors-...
With Uber Health, a doctor can send an Uber to pick a patient up to transport them to the doctor's office, and many doctors have offices in hospitals, so this service would then be illegal according to you, but it isn't.
What you probably meant to say is a medical practitioner can't call a non-medical transport for a patient in an emergency, which also doesn't seem true, but I can't find any articles that directly say that (why would someone write such a thing?).