I realize the article is trying to convince people to ideally have no alcohol at all, advice I consider to be sound.
But in terms of the question in the title, to me, "moderate drinking" is where your drinking doesn't impact those around you, i.e. no one around you is disturbed and no one really notices that you sometimes drink. Regardless of whether you believe drinking should happen less, indisputably, people who let themselves get drunk such that it causes them to be obnoxious or possibly even violent should absolutely be criticized for their level of drinking.
Back to the advice though, I've found that even a single beer or glass of wine can make me feel tired the next day, because I don't enjoy the feeling of fatigue, I largely avoid it and probably have less than 12 units of alcohol a year. I do still somewhat often (maybe every few weeks) enjoy having 1 or 2 Heineken 0.0's.
But in terms of the question in the title, to me, "moderate drinking" is where your drinking doesn't impact those around you, i.e. no one around you is disturbed and no one really notices that you sometimes drink. Regardless of whether you believe drinking should happen less, indisputably, people who let themselves get drunk such that it causes them to be obnoxious or possibly even violent should absolutely be criticized for their level of drinking.
Back to the advice though, I've found that even a single beer or glass of wine can make me feel tired the next day, because I don't enjoy the feeling of fatigue, I largely avoid it and probably have less than 12 units of alcohol a year. I do still somewhat often (maybe every few weeks) enjoy having 1 or 2 Heineken 0.0's.