We're social creatures. When it comes to an interaction between people, do not underestimate the social angle. If it's not working on that level it's going to be hard to make it work in other ways, too.
It's as if the hiring process is really two-fold: first, is the formal interviewing process - during which your suitability for the role is determined - and second is pledging the greek-letter organization/start-up - during which your suitability for hanging-out is determined.
For example, at Google we place a big emphasis on "Culture fit" during our hiring process, but we have a very diverse workforce. My team and I share few common interests outside of work, but we're all able to get together in a room, communicate effectively, and generally enjoy each other's company.
In the past, I have worked with people that I can't wait to get away from. With these people it was a really challenge to get good work done, because to work effectively requires good communication. It's a lot easier to communicate if you actually enjoy talking to the person.
None of this has anything to do with musical taste, hobbies, or drinking habits. It's to do with attitude, courtesy, patience, and other character traits. Each workplace is different and different kinds of people will thrive or fail depending on whether they fit the culture of that workplace.
Like I said in another comment making a similar point, I completely agree. It feels like the industry has been hijacked by people who were actively ejected from all cliques in high school, and now they create their own cliques around them and eject people arbitrarily because "they are not like us".
The truth is, those people had given up and became toxic to everyone around them. It was time that they move on.
Anyhow, whenever I hear the defense of "professionalism" I become fairly suspicious of the circumstances.
The point I am trying to make is that if someone says "he/she is capable and behaves professionally, but the culture fit is just not there", that's when I become fairly suspicious of the circumstances.
I personally would never work somewhere that I was forced to listen to other people's music.
It will just make the hiring process more strict. I know France has these sorts of rules in place and many companies didn't want to hire anyone without experience because it was very difficult to fire someone once you hired them.
Have better management processes so you can solve problems of "cultural fit" rather than just firing people.