When politics — of the good or the bad kind — mess with our enjoyment of a book, it’s usually because the author’s proselytizing impulse has muted whatever is interesting or particular about his way of seeing. Tolstoy’s novella “The Kreutzer Sonata” is a bad book, I think, not because it is the work of a nutty Christian ascetic, but because its nutty Christian asceticism has stamped out everything generous and curious and noticing in Tolstoy’s imagination.
I've read "The Kreutzer Sonata", and I agree that it's one of the viler things I've seen stamped with the name of an author whose works I have otherwise enjoyed.
My own personal "good read, bad politics" experience actually falls into roughly the same vein as Tolstoy's Folly: Yukio Mishima's œuvre. For a guy whose writing was luscious to read, his sensibilities veered between being impenetrable and insufferable — and it was enlightening to discover that his fellow Japanese, both authors and countrymen generally, rolled their eyes at him too.
Mishima, too, suffered from a narrowing of curiosity, something that started early in his career when he realized his one main subject was himself (Confessions of a Mask). By the time Mishima got to the end of the Sea of Fertility tetraology, it was clear he was in too much of a hurry to hand in the manuscript and execute suicidal political theater to care about whether or not it was actually a good book, or to care whether or not the amazing promise of the first two installments had been blocked by a worldview that had contracted like an asthma victim's airways.
When I recently moved cross-country, I got rid of about two-thirds of my book collection. Not one volume by Mishima made the cut — not just because I knew I would have no trouble picking them up again if it ever came to that, but because the chief appeal of his writing was in its outer beauty, and not in any inner harmonization of beauty and truth. Pretty stuff, but with nothing to share, in big part because its creator seemed all the more over time like a man with nothing to learn. Tolstoy's War and Peace, on the other hand, did make the cut — if only because I've been promising to myself I'd re-read it for far too long.