Indeed. I just checked the text we received and it does state "need to show proof" of vaccination. The presumption from patients being that if you can't or won't then no consult.
May be a matter of time until someone holds their feet to the fire. i.e.
File a complaint/suit against the doctor.
Put their registration "under question".
See if they back down if their and their family's livelihoods, reputation, safety, etc, is on the line.
Sounds like a clear violation of the Declaration of Geneva:
"I WILL NOT PERMIT considerations of age, disease or disability, creed, ethnic origin, gender, nationality, political affiliation, race, sexual orientation, social standing or any other factor to intervene between my duty and my patient"
Whether the board has a similar requirement may not have been tested in this circumstance, however malice doesn't always travel in one direction.