As somebody who amateur DJ'ed (badly, very badly I must add, I'm not suddenly cool, more the reverse):
I don't understand the logic behind the playlists in nightclubs. IMO, the choice of music is often quite bad, it leans heavily towards repetitive EDM, the playlists could consist of far more interesting music
This is such a revealing thing. And the theorizing after it on why bars do this is even more revealing (he could have just asked). But yeah people don't go to bars for interesting new music, they come for the socializing, which is a lot easier if everybody can dance along with the music, or just nod along with it if it is more a socializing place. Sometimes there also isn't a plan but just 'we should get a DJ'.
The whole list is a collection of 'I have no empathy and I also never thought about asking people about these things' btw. I really hope this is a teenager.