Jill Biden shouldn't be referred to as 'Dr.'

[csziggy]

17. In the UK many medical doctors and sugeons are not called "Doctor"

In the United Kingdom, South Africa, Australia, New Zealand, Canada and other areas whose culture was recently linked to the United Kingdom, the title Doctor generally applies to both academic and clinical environment. "Registered medical practitioners" usually do not have a doctorate; rather, they have the degree of Bachelor of Medicine (usually conjoint with Surgery). Cultural conventions exist, clinicians who are Members or Fellows of the Royal College of Surgeons are an exception. As an homage to their predecessors, the barber surgeons, they prefer to be addressed as Mr, Mrs, Ms or Miss, even if they do hold a doctorate. This is first because they have normally achieved another degree - that of Master of Surgery (MCh from the Latin magister chirurgiae) from a university. When a medically-qualified person passes the notoriously difficult examinations which enable them to become a member of one or more of the Royal Surgical Colleges and become "MRCS", it is customary for them to drop the "doctor" prefix and take up "mister". This rule applies to any doctor of any grade who has passed the appropriate exams, and is not the exclusive province of consultant-level surgeons. In recent times, other surgically-orientated specialists, such as gynaecologists, have also adopted the "mister" prefix. A surgeon who is also a professor is usually known as "Professor", and similarly a surgeon who has been ennobled, knighted, created a baronet, or appointed a dame uses the corresonding title (Lord, Sir, Dame). Physicians, on the other hand, when they pass their "MRCP" examinations, which enable them to become members of the Royal College of Physicians, do not drop the "Doctor" prefix and remain doctor, even when they are consultants. In the United Kingdom the status and rank of consultant surgeons with the MRCS, titled "mister", and consultant physicians with the MRCP, titled "doctor", is identical. Surgeons in the USA and elsewhere may have the title "doctor".

https://separatedbyacommonlanguage.blogspot.com/2007/12/physicians-titles.html

More at:
https://www.bma.org.uk/advice-and-support/international-doctors/life-and-work-in-the-uk/toolkit-for-doctors-new-to-the-uk/doctors-titles-explained

PhDs that are not doctor but that are academics may be called "Doctor" or "Professor."

So if the column writer objects to calling Dr. Biden "Dr." he should call her "Professor." Either will give her the respect and deference she should have with her credentials and experience.