Earlier quoted context omitted.
Feel free to ban anything you want at work. And the people who work there will select for if they want to be a part of it by becoming or remaining employees. (There are, of course, things that are illegal to ban) I personally want to work somewhere who values me as a responsible human being, and expects me to behave like one. The more a workplace feels like they have to micromanage their employees like children, the…
The positive aspect of banning alcohol consumption is that it's an objective measure. If somebody is a drunken lout pawing his employees, save the victim more exposure by drumming him out for the alcohol. With the possible exception of salespeople entertaining clients, there's no need to drink on duty, and if you do, there is a consequence.
The gist of what the parent comment is saying, is that, if you have a policy in place to "compensate" for a certain "negative trait," what you are actually doing is inviting _more_ of that trait, because you are signaling that your company will put effort in to help deal with that, which means that someone who needs help monitoring their alcohol consumption would be _more likely_ to work for you, thus accomplishing essentially the opposite of what you wanted.
Mature adults who do _not_ need someone else to monitor their alcohol consumption are far more likely to inherently present with the responsible, adult behaviors that you desire. But, a mature adult who can already sufficiently moderate their own alcohol consumption is going to be _less likely_ to want to work at a place where said consumption is heavily, outwardly regulated/enforced, because why would they want to be constantly told something that they have already fully incorporated into their mature, adult habits and personality?