I think it is because of a cultural expectation(that is really a relic of the 1960-2000 era in which music was a more significant cultural force then it is today). Basically everyone is living in a convenient fiction where they pretend to have great music taste because having taste in music is seen is culturally significant in way that films and television are not(even though I would argue that the 2000-today is somewhat of a golden age for television in terms of artistry and cultural relevancy, and being something "more than entertainment" but a marker of cultural identity in the same way that popular music was transformed in the 60's).
Basically there is significant social pressure to develop "taste" in music more so then television or film, even though music is increasingly splintered as a cultural force thanks to the internet, and the slow death of radio. I know that personally my exploration into music was done entirely on the internet, Im not really interested in attending shows or anything, and The only radio I listen to is NPR. Because it has become so personalized, everyone feels like their their taste is legitimate, even when they are the most entry level of casual music listener.