The ethics of musical masochism

[Elliott Carter] walked out of Orchestra Hall before the [Chicago Symphony's] 1984 performance of his Symphony of Three Orchestras because he objected to the seemingly flippant tone of conductor Leonard Slatkin's spoken introduction.
John von Rhein, "Composer Elliott Carter has chosen a difficult road", Chicago Tribune, November 22, 1992.

I always like to talk about a difficult piece before I perform it. ... I meant no disrespect to Mr. Carter.  Simply because I don't like a particular piece of music doesn't mean I can't lead a performance. I even recorded the Pachelbel canon. 
     ... On the other hand, I still don't like Mr. Carter's symphony. ... I don't hear much in his work at all.  It's just a series of mathematical gestures, piled on with needless complexity.
Conductor Leonard Slatkin speaking to Tim Page in "An American Conductor Succeeds at Home", New York Times, May 20, 1984.
____________________________________
I take it as obvious that Leonard Slatkin's remarks in the above New York Times interview are those of an arrogant asshole with a seriously underdeveloped musical mind and a grotesquely inflated sense of self-importance.  What caught my eye in this interview, however, was not so much Slatkin's display of philistinism and rudeness - he isn't the only baton-waving hack to have insulted Elliott Carter - as his bragging about having performed musical works he actively dislikes. Slatkin's musical masochism made me wonder if, aside from being irrational, it is unethical for a musician to give public performances of music he actively dislikes and which he is not contractually obligated to perform.

To my surprise I was unable to come up with a convincing answer.  On the one hand, it seems that if a performance is competent enough to please experienced listeners, then the musician's feelings about the work should have no moral significance because they are irrelevant to the transaction taking place in a concert hall.  On the other hand, it seems implausible that a musician could give his best to works he finds distasteful.  In that case, the listener, even if satisfied with the performance, would end up being cheated by the musician's diminished commitment to the music.

Since both positions seemed defensible, I decided to abandon further scrutiny and instead listen, once again, to Carter's Symphony of Three Orchestras - a complex work, to be sure, but one which, as a musical portrait of Manhattan, is no less vivid and dramatic than any of Richard Strauss' programmatic tone poems.  From a seagull circling high above the Brooklyn Bridge (the long and breathtakingly atmospheric trumpet solo with which this work begins) to the distant din of car horns and sirens familiar to anyone who had lived in a high-floor apartment near one of Manhattan's busy avenues (the obsessively repetitive woodwinds in the closing bars), it is hard not to think of Carter's symphony as a modernist love letter to New York City.  The full meaning of this love letter may reveal itself only gradually and with some difficulty, but then this is characteristic of anything that deserves to be called a work of art.[1]

__________________
[1]  It is unfortunate that the only readily accessible recording of Carter's symphony is the poorly edited Sony CD re-issue of the 1977 studio recording conducted by Boulez.  (The original CBS Lp had much better editing, although it still needed at least 15% reduction in the artificially boosted volume of the first 4 minutes.)  I got the full measure of this work only after I came across the 1986 live FM broadcast of the performance by the Philadelphia Orchestra under Dennis Russell Davies. The performance may not be perfect, which is understandable given that the orchestra had very little if any experience with advanced modernist music after the 1936 departure of its musically adventurous director Leopold Stokowski.  Yet it allowed me to grasp the structural organization and the emotional significance of the symphony far better than Boulez' s studio recording.