New Zealand - you gotta be this old to have rights.

[Angrboda]

Health care costs aside. Unless you are in favor of all aspects of your health being government mandated.

Do you consider any other lifestyle choices to have as significant a monetary cost to society? Obesity comes to mind, but that's not a lifestyle choice. The idea that riding motorcycles incurs a comparable amount of cost to society as smoking is probably not borne out by the statistics. You're essentially making the argument that if we ban smoking for the societal costs, we would be justified in banning X for having similarly comparable costs. I don't know what you're putting in the place of X. Do you?