"Whether abstainers choose not to be as social or whether organizers of social occasions involving drinking exclude abstainers is unclear. Abstainers may prefer to interact with other abstainers or less social people. Alternately, abstainers might not be invited to social gatherings, work-related or otherwise, because drinkers consider abstainers dull."The argument is that drinking benefits one's social network and the paper is one of two that show a correlation, at least for male drinking. A separate stereotype says females tend to be more social than men, perhaps meaning men rely more on crutches. For me at least that's true--I use(d) drink as a social lubricant, depressing my sense of social unease while participating in a social ritual. So drink is both an indicator of my social participation and a facilitator of it.
I wonder though whether this is as true today as it used to be. My impression is that drinking, at least liquor, is down. Certainly the bars at the Kennedy Center don't seem to be doing the business they used to. Maybe someone should do a study of coffee drinking?