Tolstoy's nastiest story - maybe his worst

Tolstoy's story The Kreutzer Sonata, which I'm reading now in the Pevear-Volkhonsky translation in "Ivan Ilyich and other stories," is a great story in its peculiar way - obsessed man on long train journey tells a stranger of his horrible marriage and, ultimately, of his crime - but also a nasty piece of art that I didn't enjoy reading the first time I read it and ditto now on re-reading. The madman's narration is filled with loathing, contempt, and most disturbingly a vitriolic misogynism - he hates women, marriage, his marriage, his wife, etc. I'm about half-way through, and have heard him talk about the horrors of his honeymoon, the fake affection he's felt for his wife, his guilt over his early debaucheries, his supposition that all marriages are as horrible as his, and so forth. The action, so to speak, picks up in the second half; the first half is all venting. The question confronting us is: to what degree, if any, does this man speak for Tolstoy? Tolstoy's frustrations with his own marriage are well-know and often chronicled (and filmed), but clearly this character isn't Tolstoy, he's a lunatic. And yet: what would draw Tolstoy to write about this material? How could he make himself do it if he didn't, in some shred of his consciousness, believe it? Writers aren't their characters (Shakespeare is not Iago), but there's something particularly creepy about this instance - partly (mainly?) because it's not a tale of horrible tragic action but a long exposition of unrelenting nastiness. Dostoyevsky's Notes from Underground is similar - but far more sympathatic because of the deep sorrow we feel for the Underground Man.