A lot of great figures in classical music have held political views diametrically opposed to mine. Beethoven's admiration of the "ideals" of the French Revolution is well known, though he had many aristocratic friends and patrons. Wagner, before he discovered that the support of the King of Bavaria could be useful to him, was a supporter of the Revolutions of 1848 and was a wanted man in Saxony for a time. Nikolai Rimsky-Korsakov (1844-1908) disliked his former mentor Mily Balakirev's pious Orthodox monarchist conservatism, was critical of the Tsarist regime towards the end of his life, and sympathised with student protests against it. Conductor Arturo Toscanini (1867-1957), who according to Norman Lebrecht had only turned against Mussolini when it became clear that Mussolini would not abolish the Italian monarchy, said after World War II that he would not return to Italy as long as the House of Savoy were still reigning. Cellist Pablo Casals (1876-1973), despite having owed his early training to the generosity of Queen Maria Cristina (1858-1929), supported the Spanish Republic that ousted her son Alfonso XIII.Of today's classical musicians, I've heard that one very well-known British conductor is privately a republican, though as he has made no public comments to that effect I won't name him here. The less said about a certain Australian conductor, the better. I hope that none of the British performers I admire are republicans.
In general I don't envy Soloists, who fly from hotel room to hotel room, and am happy to be an orchestral cellist. However, sometimes I wish I were prominent enough in classical music for my monarchist views to be Noticed.
But I can take comfort in the fact that Brahms, despite a youthful essay arguing that music should be "republican" in the sense of being accessible to all, was politically a staunch monarchist and once got very angry at a friend who had mocked the young Kaiser Wilhelm II. Haydn was a monarchist as well; the last music he played when he was dying in 1809, reportedly with great feeling, was his own Kaiserhymne. Verdi, near the end of his own life, was overcome with grief at the assassination of King Umberto I in 1900, wondering if his own 1859 opera "Un Ballo in Maschera" (inspired by the 1792 assassination of King Gustaf III of Sweden) could be in some way to blame. (It must be admitted that most Italians were probably rather more moved by Verdi's death the following year.) Brazilian composer Carlos Gomes (1836-1896) remained loyal to Emperor Pedro II after the 1889 coup and refused the new Republic's request to compose a new national anthem. Bruckner, a devout Catholic who was humbly moved to be decorated by Emperor Franz Joseph and considered moving to Mexico to serve his brother Emperor Maximilian, was a staunch monarchist. Perhaps more surprisingly, as an article in The Critic revealed, so were musical modernists Schoenberg and Stravinsky, who long after the Revolution never lost his reverence for the Russian Imperial Family. Benjamin Britten (1913-1976) was famously pacifist, but as far as I know had no problem with the British Monarchy and counted Prince Ludwig of Hesse (1908-1968) & his wife and the Queen's cousin the Earl of Harewood (1923-2011) as friends.
I guess this just goes to show you that musicians can be all over the map politically!