This reminds me of some thoughts I had about Joseph Haydn recently. Though the case of Nigel Milsom seems extreme, there are quite a few other examples of artists who lived on the edge or outside of society. Art, since probably the French Revolution, has been the province of the individual, often tortured, genius. What is fascinating about Haydn is that, as much of his career came before the French Revolution, his kind of genius falls outside our usual narrative frame. Except for an unfortunate marriage, Haydn did not live a tortured life. Despite this, he was one of the most radical, creative and inventive composers in all music history.
What does this tell us about aesthetics and the history of art? Plainly we can separate the creation of brilliant artworks from any kind of political context. You can be a progressive artist while writing music for the nobility as Haydn did. As a matter of fact, the nobility were also the primary audience for Mozart and Beethoven as well.
Here is the first movement of a Piano Trio in C major by Joseph Haydn played by the Melbourne Piano Trio: