I've never considered gaming a drinking sort of atmosphere. Largely, I think, this is because of where I've played.
When I was at university and we played on campus, people usually wouldn't drink because they'd have class after the game, or at least have to drive home. Keep in mind, in Australia the drinking age is 18, and we had two bars on campus, so it's not like people couldn't have been drinking if they'd wanted to be. That said, more often than not we played in areas away from the bar, where you weren't allowed to have drinks, anyway.
During university and since, most of my gaming has taken place in the evenings, at someone's apartment or sharehouse. Obviously, then, the issue becomes one of having to drive home afterwards - the host(s) or anyone being given a ride home (many of my friends were not and are not drivers) could drink, but I can't remember it ever having happened.
I guess, in total, the people I game with have a culture that says one or two people drinking while the others aren't won't make for a good game, and maybe that anyone drinking won't make for a good game. I think that last depends on the kind of game you want to be playing, but I have to admit that the kind of games I like to play aren't very workable if people are getting even a little bit tipsy and silly.