That "offers little to no positive effects" comment suggests to me that you have limited personal experience with alcohol. The primary benefit I (and I think most drinkers my age) derive from alcohol is social: it helps me make new friends and connect more closely to existing friends. Lots of people drink, and it's easier to become friends with those people if you also drink. If that isn't enough LW lingo for you, drinking is a Schelling point.
Also, what do people have against placebo effects? Quoting myself seems dangerously egotistical, but "a placebo effect is still an effect." Maybe someone should write a top-level post about this.
I've had enough experience to compare interactions with and without alcohol, and I've noticed it's much more difficult to connect with anyone who's been drinking, even if I've also been. Merely personal, but with no alcohol in my regular life, I still gain friends easily, now having gained far above my Dunbar's Number. Have you tested if it actually is more difficult if all parties are sober?
I'm against this particular one, since as a placebo, something lacking the negative effects while achieving the positive placebo effects would be much more awesome.
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.