Wow, I have never seen much alcohol available at conferences in my own field. Often they are held on university premises instead of at hotels like in the linked article, and so perhaps serving alcohol is forbidden there. All one gets is free coffee and some cakes. Sometimes attendees will decide to have dinner together after the day’s programme, but that just means a restaurant where each person can decide whether to order a glass of wine or not, and certainly not an open bar.
A while back I read the memoirs of one prominent scholar in my own field. He claimed that conferences are so often used for impetuous sex between academics, whether single or married. That’s another dodgy side I have never noticed personally. It makes me wonder if he was exaggerating or I have simply been blind to it.