Is this phenomenon unique to the information technology industry? I don't know what they do for fun at pharmaceutical conferences, but I suspect alcohol is often involved.
Society has a bit of a drinking problem. (Some other societies, like Russia, have a bigger one. Some have less.) Next question? :P
Maybe, but hosting happy hours after conferences is not a symptom of that. It's a symptom of our various societies having discovered alcohol, and then built up a lot of social norms and customs around it.
It's like saying that our society has a violence problem because people like to gather around a television and watch men hit each other while trying to tug a ball around a field.