Counter-example: I went on one bar crawl with student organization members at college. The fun part was opening up and talking honestly with other people I typically had a more professional relationship with due to the nature of the organization. We saw a live music performance by a small band at the back of one of the bars, and every time things seemed dull, we changed locations and visited hidden-away parts of the city at small bars that were difficult to find.
The novelty of the exploration and speaking openly to people was really fun. I suppose we could have explored the city sober, but I doubt that the vast majority of the other people would have spoken unreservedly without alcohol. I wouldn't do it again at my age, but it was a fun memory. It wasn't necessarily drinking that was the fun part, but rather the activities it enabled.
The idea that alcohol helps you speak unreservedly when you otherwise wouldn't is one of ideas that bothers me the most. If you wouldn't say it unless you were drinking, it's either better left unsaid or something you should be training yourself to become comfortable (or at least capable) of talking about sober. Just because society at large promotes alcohol as an acceptable way to paper over not developing these skills doesn't mean it's better off for it.
This is a good way put it, and it could be a useful goal for the individual to aim to speak as comfortably sober as under the influence of alcohol.
However, it's very likely that most people don't act like this, or even know that this is a goal to work toward. As an individual, I can act (or aim to act) unreservedly sober, but the other people I want to know better might not; and it takes more than one to carry a conversation.
It's possible to only choose friends who are comfortable opening up without alcohol (I believe this represents most of my current social circle, though this was coincidental versus by design), but I believe I would have missed out on meaningful friendships in the past if I filtered out potential friends based on this criteria.
It's not only about whether you personally are comfortable talking about something. It's also about whether the people you are talking to are comfortable with it.
The novelty of the exploration and speaking openly to people was really fun. I suppose we could have explored the city sober, but I doubt that the vast majority of the other people would have spoken unreservedly without alcohol. I wouldn't do it again at my age, but it was a fun memory. It wasn't necessarily drinking that was the fun part, but rather the activities it enabled.