I know it would be more generous and fair to give each of the following writers his or her due by examining the historical, biographical, and sociocultural factors that contributed to the dickish behavior on display, but hey! we're on the internet. If you can't spew hate-filled vitriol without regard to the complexities of human nature on the internet, where can you? (Unless you're lucky enough to get a book deal.)
All joking aside, the ethical question of whether it's right to read a writer or admire an artist who exhibits such antisocial behavior as those below is a thorny one. Just where do aesthetics leave off and ethics begin? Does our admiration of The Artist excuse us from passing judgement on his or her life? And where does biography leave off and an artistic legacy begin?
Or should we agree with that wit Oscar Wilde, who once claimed that "There is no such thing as a moral or an immoral book. Books are well written, or badly written. That is all."
Or, on the other hand, with Georges Bataille, who argued contra Sartre, that "Literature is not innocent. It is guilty and should admit itself so."
Hamsun looks dapper here, in 1925, with his wife Marie and the family dog, but twenty years later he'd be put on trial in Norway for his allegiance to the Third Reich. It wasn't bad enough that he gave his Nobel Prize medal to Goebbels; no, Hamsun actually went so far as to eulogize Hitler.
Exhibit #2: Patricia Highsmith
According to playwright/biographer Joan Schenkar, the acerbic, virulently racist, anti-Semitic, and malevolent Ms. Highsmith once threatened to leave her fortune to the Infitada.
Exhibit #3: Louis-Ferdinand Celine
Celine's hatred crackles not only through the pages of his work, but of his life as well. Jim Knipfel sums it up most succinctly by writing that Celine, anti-Semite and collaborator with the Vichy government, "was [to put it mildly] not a very pleasant fellow."
Maurice Barres, Ernst Junger, Gabriel D'Annunzio, August Strindberg, Yukio Mishima, Ezra Pound, Ayn Rand, Francois Villon, D.H. Lawrence, Anne Perry, &c. &c. &c.