Yes, the doctor's advice is reasonable and no the doctor is not smoking at a lung cancer appointment. The premise is that they are messing up off the job. If you think an oncologist shouldn't be able to get as good of a job because they smoke cigarettes or eat burgers, that is where we disagree. Apart from calling that illiberal or saying it has negative utility in its consequences, I don't know how to argue that; it's a values difference. I appreciate you actually taking the position, though.
Same for your cop positions. You say they should, I say they shouldn't. If it's clarifying, I can add that I agree that cops should be held to a higher standard while being cops, ie. that things like qualified immunity are working in the wrong direction, and that they shouldn't be held to a lower standard, on- or off-duty.
As far as I'm concerned, speeding tickets in the course of your private life are between you and the ticketing authority. If he's not paying his fines, if he's violating the social contract, sure, escalate. If we want to punish speeders with more than fines because of endangerment, like the article strongly suggests, sure, change the law. But as long as he's compliant with his fines and we're only giving him fines, it's not just to continue to pile on consequences.