I enjoy drinking alone, exercising alone, traveling alone, sitting alone, working alone. I don't really think I'm that weird by objective standards, there are also things I like doing with people (I'm married and have a family), but as a sometimes introvert, I definitely value time alone, including relaxing with a beer.
Related, when I went to university, I lived in residence and i remember sitting by myself at meals and having people come and basically think they were doing me a favor talking to me, because only a loser would want to sit by himself. I found it both annoying (because I wanted to be alone) and condescending (because people see you alone and come talk to you like you must have no friends) - all that to say, society seems to look at you funny if you enjoy being by yourself, so I wouldn't read too much into sllo drinking being shunned specifically.