I didn’t know commercial divers had to pass repetitive physicals.
I think it depends on what type of diving you are doing. If you are training inexperienced divers for pay, maybe you have some professional obligation to prove fitness? If you are diving for fun, it is really between you and your buddy. You could refuse to buddy with someone who appeared physically unfit, but that is not as easy to tell as you might think. Could a dive master refuse to lead a diver that looked unsafe? Again, you can’t always tell by looking. It is usually more obvious after the dive is underway. You could make a similar argument for poorly trained/ inexperienced divers.