I find myself returning to the question: what is music? What kind of thing is it? What conception of music do we hold?
One answer might be that music is whatever we want it to be.
But this radical subjectivism is unlikely to help in finding a basis for a music education sponsored by the state. (Or would it? What do you think?)
Another response might be that music exists as a physical object in the form of sound.
This second answer has great provenance within the academic study of music and in conceptions of music that have underpinned beliefs about music education. With this answer comes the proposal that listening is the privileged mode of musical engagement. 
Ian Cross suggests that this was the case in 19th and 20th century musicological literature as he makes a case for the re-orientation of the cognitive science of music towards thinking of music as human behaviour. And here then is a third answer.
In this way ‘… music is more than complex patterns of sound that are beautiful, expressive, and listened to because they move us … ‘ 
‘… the overwhelming weight of evidence from ethnomusicology suggests that we should conceptualise music as a medium for human interaction that is embedded in, and is efficacious in respect of, social processes.’ 
The way we conceptualise music has implications for what might be deemed to be a ‘knowledge rich’ music education. And if a key arbitrator in this is to be the authority of scholarship in music then privileging what Gary Spruce refers to as aesthetic listening to the art work as an autonomous object is no longer justified.
 See Cross, I. (2012) Cognitive Science and the Cultural Nature of Music. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1756-8765.2012.01216.x
 Spruce, G. (2016) Culture, society and musical learning. In (eds) Carolyn Cooke, Keith Evans, Chris Philpott and Gary Spruce, Learning to Teach in the Secondary School. Routledge.