Hi, I'm back.
Anyway, it was mentioned before, but it's a very important fact that what's dangerous isn't alcohol, but binging (which, by the way, is the norm in places other than New Zealand, and from what I've heard, not really uncommon in UK or the States).
Not only is drinking in moderation not harmful, but it's actually beneficial. It has a clear effect of lessening the risk of cardiovascular disease and thus increasing life expectancy. It would be simply silly to ban this, since it would only lead to people having heart attacks younger, which would be costly to the society and unpleasant to the people as well.
Banning public drunkenness more explicitly would not be a bad idea, but even here I'm inclined to think it's pretty much impossible to enforce.