Yes because doctors are licensed by their specialty. Which is only achieved by years of direct subject matter training...coupled with continuous education.
The doctor in question is not licensed for infectious disease.
You should never trust a doctor speaking outside of his expertise.
However most of the celebrity doctors do that every single day which is an insult to the entire medical profession.
In the US at least that isn't how physician credentialing works. Doctors are licensed by state medical boards. In addition, some go on to earn certification from specialty medical boards but those certifications are not legal licenses.
In general we shouldn't blindly trust any single doctor about an important or risky topic, even within their own specialty. Always get a second or even third opinion if practical. (I agree that most celebrity doctors are little more than quacks.)
The doctor in question is not licensed for infectious disease.
You should never trust a doctor speaking outside of his expertise.
However most of the celebrity doctors do that every single day which is an insult to the entire medical profession.