However, it seems to me that if an adult wishes to partake of something in the privacy of their own home, they should be free so to do.
We do not, for example, apply an additional tax to rugby players who may need the ACC more than non-rugby players. We do not try and ban it because there is an increased injury risk. We do not charge drunks for the free rides home they get on Police 10-7 or for the additional healthcare and related injury costs that might arise out of their drinking.
Generally I agree with the bold bit. Although passive smoking by kids is claims to have a high health cost.
Rugby: results in some injuries but keeps people fit - stopping people from playing rugby, may simply increase the chronic disease burden. Ditto other sports.
Alcohol: is heavily taxed, so the government has a compensating revenue source. I have no objection to this.
I note that alcohol, when used in lawful manner, does not harm bystanders. Generally, someone has to drink alcohol and break the law (assault, drunk driving, parental neglect etc) to cause harm to others.
The same can not be said of smoking tobacco. Although it could be said of chewing tobacco, snuff etc.