"You wouldn't expect a political rant from The London Symphony Orchestra would you?"

No, but I might expect a gentle nudge in a given direction or some chiding about the direction I might be going. Composers of "serious" music have often been political beings, and symphony ochestras, choral groups and the like often schedule works in their concerts that carry a message pertinent to the day. And, many conductors of these groups, in their introductions to the music, have made thier opinions clear to the audiences. It may not garner the headlines that a Ronstadt does, but it happens in that milieu as well, because that's what artists do.