Not him, his victims
"Victims" is the right word. Ethical practitioners of healing arts do not use the implicit power and authority of the therapeutic relationship for personal benefit. That includes sex and politics.
A health care provider has an implied "do what I say or you will suffer" tacked on to all he or she says within the therapeutic relationship. There are lots of us who are ready to question it, who don't take anybody's word for it, but the fact remains: healing people gives you power over them. And it is wrong to use that power for anything other than healing them.
Note that I'm talking about the personal therapeutic relationship here, not the community status. Nothing wrong with a health care person having a political life, or even using the status in the community that the healing art gives them in a political way.
There was an obstetrician I know of who ran for office and his ads featured babies and said "Dr. {name} will Deliver for Wisconsin". Not an ethical issue. A little cheezy, sure, but this is Wisconsin and we like cheese. Now, if he had told his patients they should vote for him (or his party, or his candidate) because he's their ob and he said so, or because it would be a factor in their treatment, that's abusing the authority of the therapeutic relationship.
And that's exactly what the sign does.
HCR has not affected the doctor yet. It has affected his patients. For the better, if it caused them to seek a more ethical doctor.
---------------------------------------
Why, yes, I did give up something for lent. I gave up making sense.