As a practical matter, it is NOT legit.
Even the deans of Yale and Harvard Law who are JDs don’t use the title “Dr.”
As a practical matter, there is no “higher level” or academic status that legitimizes the use of “Dr.” by a JD.
No self-respecting JD (who does not also have an MD or PhD) a uses the title “Dr.” Its not done.
Meaning you don't like it.
The article itself is ALSO evidence that a number of lawyers are doing it. That is, it is legal, legitimate under industry ethics guidelines, and some are actually swimming in the pool and not just dipping their toes.