I love freedom. I support freedom. Freedom is fun.
I think everyone should be free to do any thing they want, even if it is harmful to themselves, as long as two conditions are met. First, the chooser of the freedom in question must have reached an age when they can make the decision responsibly. Second, they must be able to enjoy the chosen freedom without harming others or disrespecting others' freedom.
To choose smoking and meet these conditions, smokers obviously need to be sure they are not harming the health of their children and/or family members via second hand smoke. Difficult but manageable I would think.
More difficult and less manageable is how to choose smoking without consuming more than one's fair share of health care expenses. We know smoking is very unhealthy and that it leads to many costly medical conditions. The burden that smokers put on society to pay for their poor health is enormous. I know that medical insurance premiums are higher for smokers but "smoking habits" are one of the most famously misreported lifestyle choices in the history of the medical insurance industry. Let's be honest; non-smokers pay for the majority of smoker-related health care problems and, since smoking is a choice, those who choose it impinge on the freedom of those who do not.
I support freedom but smoking is not free and is difficult to do freely.