Comment by vintermann

Alcohol doesn't create social cohesion chemically. This is a learned effect - there are societies where they had different beliefs about alcohol, and there it doesn't have this effect. This is a really old finding of anthropology. (Of course, in today's global world, beliefs about alcohol get homogenized, so there are ever fewer of societies where they have diverging beliefs about alcohol effects.)

Moreover, it seems likely to me that just like the "relaxing" effect of nicotine, this advantage is "stolen" from daily sober life. If we as a society agree to judge each other less harshly when we're drink, I think we will just naturally judge each other more harshly when we're sober.

However, unlike with nicotine, where the effect is physical and individual (you relax when you get nicotine because you get stressed by physical addiction when you don't), for alcohol it's social and collective. You suffer the negative effect (social pressure to basically be more uptight in everyday sober life) whether you participate or not.