I don't recognize abortion as legitimate and I don't recognize that we have unlimited dominion over our own bodies. A society has a vested interest in imposing a set of standards upon its people which can include, and should include, prohibitions are certain substances that harm individuals and society. I am fully willing to grant that there is a legitimate interest in a society to restrict the freedom of people to follow their passions blindly.
I am not a libertarian or an anarchist.
Tobacco is harmful for one's health, but relatively harmless, in fact beneficial, to the mind. Tobacco users show a slight increase in IQ. Now, is it wise to become a chain smoker? No, but there are at least some benefits to it, even if we could almost certainly make a reasonable argument to ban cigarettes (though pipes and cigars have vastly fewer problems).
Alcohol is also actually good for you in moderate dosages. You can indulge indefinitely in alcohol with virtually no ill effects if you do not over indulge at any given point. Only people who are disposed to addiction (like American Indians) should outright abstrain from alcohol. The rest of us should indulge in it with moderation and temperance and enjoy the benefits to our health and well being from such.
Moreover, just because there are some legal things which are harmful does not mean we should legalize another harmful thing. This is a form of fallacious argument of the sort "et tu quoque" (and you also).