He is not rejecting anyone. He is asking them, rather politely, to see someone else. If they come in, he doesn’t ask them how they voted, he treats them.
If you voted for Obama, seek urologic care elsewhere. Changes to your healthcare begin right now -- not in four years."
That sounds pretty definitive, although it is not directed at any specific patient. I would not be surprised if he has to answer a medical board complaint over this. His sign should have said something like:
If you supported Conress' recent Health Care Reform legislation, the staff of our medical practice would appreciate your seeking health care somewhere else from now on. We will gladly assist you in transferring your medical records to your new health care provider while they are still considered private and confidential.