A pint of beer contains a little more than a tablespoon of ethanol, and I suppose it adds up, but two gallons per year?
So I did the math. A legal drink is .6 ounces of ethanol. 2.3 gallons is 294.4 ounces of ethanol. So the average american drinks 1.34 drinks per day, or the average American drinker drinks slightly less than 2 legal drinks per day, which the article even admits isn't unhealthy. It really does add up I guess.
Also, it's a common mistake to make to assume that everyone wants to optimize their health, or worse, that we should force everyone to optimize it. There's pretty much no valid health reason to drink either soda or alcohol, to eat pizza, or to smoke a cigarette. But that's not the reason that anyone does any of those things. As it turns out, my body is not a temple, and there's no math equation that can calculate an ideal life.