I think now that political discussion here has been curtailed, its only ideology that is left. Whether we are conscious of it or not, we all have some sort of ideological bias. That's not necessarily a problem, but how it seems to work out so badly in online discussions is.
I think there are links between the experience of modernity and artist's responses to it.
I think that its contribution to any decline, in terms of the music alone, is overrated. There might be a stronger argument in terms of how ideological approaches informed by modernism negatively impacted on music, but I think that's more or less limited to those who where working in music rather than the audience.
I think social justice is political. If you look at what reformers in music education like Zoltan Kodaly did, and also Jose Antonio Abreu (who founded El Sistema in Venezuala, which I mentioned), their work was at least in terms of its impact, political. It must be said though that their aim was to build up music education, and their first priority was to achieve their goals, not to serve purely political interests. Abreu, for example, worked with whoever was in power. His program gave many gifted young people a way out of poverty, drugs and violence. His longer TED talk is also on youtube, but in this short clip you can see some of the poor conditions he was working in.