That's a great question, asked by an Anon on the Richard Peck post, and it's the third time in as many days that I've seen it pop up. First, poet Marilyn Nelson had a question over at her Facebook page: "how do we measure the value of the art made by an artist who is also a monster, who is known to have done monstrous things?" Then I saw at Judith Ridge's Misrule a discussion about A.S. Byatt's contention that writers for children have a greater than average propensity to be terrible parents, a hypothesis that neatly dovetails with the case, discussed on Marilyn's page, of Anne Sexton, a sometime-children's poet who sexually abused her daughter.
First, I don't think it takes a monster to do monstrous things--Anne Sexton was a deeply disturbed woman, not a monster--but I wonder what it might take to cause me to boycott an author, or to use an assessment of his or her life in qualitatively judging his or her work. One thing is for sure: "by their fruits ye shall know them" does not apply to writers!