I tweet the following semi-periodically, and it probably deserves a longer explanation:
"A periodic reminder of how much relevance an artist's personal life has to the aesthetic evaluation of their work: none."
There are two primary reasons behind this: it is difficult, if not impossible, to know enough about an artist's personal life to make a definitive moral judgment about who they are, and the decision to let ethical questions dictate aesthetic responses has a tendency to crowd out the time one might take to enjoy art.
In order to get this argument off the ground, I have to stipulate one--hopefully uncontroversial--element: all human beings engage in a mix of good and bad behavior, and almost everyone's bad end includes some actions, opinions, and mental states they would prefer not to be made public. Nick Hornby has a riff on this in High Fidelity, where the narrator, having just admitted to having done five terrible things to an ex, asks his readers to think of the five worst things they've done to someone they were dating, and then asks them how they feel about being judgmental. People tend to want to accentuate the good things they have done and ignore the bad, or simply questionable, things. Outside observers who are not neutral tend to focus on the good or the bad. Consequently, the information that's available to us about artists from secondhand sources tends to be either good or bad, depending on whether it's a friend or an enemy speaking. But the information these people have is limited, and only the artist will ever really know.
Which is, as it happens, how it works with most of the people we meet: we just accept as a fact that their personal mix of goodness or badness remains unknown, and so we judge on those elements of their personality that are visible to us.
For artists, whose personalities tend to be in larger view, intentionally or not, the judgments appear to be trickier. How do we feel about Roman Polanski, or, assuming the charges are true, Woody Allen? I liked Michael Chabon's The Amazing Adventures of Kavalier and Klay, and The Yiddish Policemen's Union, but I also read the book of essays where he gets very judgmental about his single mother's dating habits, and humblebrags that even though he wasn't cool, he definitely slept with at least one of her friends, and many other women he found desirable. What do I do with that? Jonathan Franzen appears to want to be the world's worst posthumous friend to David Foster Wallace, and seems to have some issues with anger and women. Dan Harmon appears to be obsessive and alienating to a number of people he works with, and the Hollywood grist mill provides more examples than I could even list here.
(I also note that the routine excess of popular musicians never generates the same ire, or certainly doesn't now. The last things I can think of are David Bowie's saying England was ready for a fascist leader, and Eric Clapton's effusive praise of Enoch Powell, both of which have obviously harmed their careers. (It's also, I believe, not entirely clear that Clapton does not still agree with Powell))
The issues multiply with past artists: what are we to do with Hitchcock's misogyny (especially as it is mostly absent from his earlier British films)? Should we lend credence to the rumors about Grace Kelly's active personal life? The grubby details of Barbara Stanwyck's rise to fame? Spencer Tracy's multi-decade affair combined with a refusal to divorce his wife? How should we react to the more sordid details of W.H. Auden's personal life, or T.S. Eliot's anti-Semitism and crypto-fascism? Ernest Hemingway leaving his wife and young child for his mistress? Scott Fitzgerald's drinking, and treatment of his wife? How about Jean-Jacques Rousseau sending his children to the orphanage? And what of the people whose morality we can discern nothing at all: Homer, for example?
At this point, there are two options: one is to define a standard of those shortcomings which are morally relevant to consider, both present-day standards and those which are appropriate for the time. Failure to do the latter would require excluding large swaths of culture for insupportable stereotyping by race and gender. The former is also revealing, in that there are a number of indiscretions which are not considered to be reasons to boycott an artist's work. Even so, one can define an acceptable standard, assess the information available, determine what in it is reliable and does not come from a source that might be compromised, and come to a conclusion about whether the artist's work can be supported. This is, not to put too fine a point on it, a lot of work, and fully engaging in this process would eat up more time than the average book or movie would be worth.
The other is to conclude, perhaps even reluctantly, that ethical questions are separate for aesthetic ones, and aesthetic reasons should guide our decisions about what to consume. Works of art can get away from their creators, after all: even the staunchest defender of the view that Mark Twain was a racist has to acknowledge that Jim is the human and moral core of Huckleberry Finn, and Woody Allen can say something important about the need for moral standards in Manhattan even if he's a lout. If Roman Polanski makes a good movie, it is good because it is in some important way human, or truthful, or beautiful, or excellent, even if its director is none of those things. The capacity to create something unexpectedly great is one of the formative reasons for reading and watching and listening. And, moreover, the capacity to recognize in the thing one has done wrong its meaning is the redemptive possibility of art, and not to be taken lightly; Fitzgerald's late-in-life stories are his failures realized, someone who understands the depths of what he has done wrong. The emotional core of Annie Hall is those final scenes in which the character understands exactly how and why he was wrong, and creates something to fix it, which leads him to fix himself.
All that being said, I am fine with moral reasons working on the margin of aesthetic choices: vita brevis, longa ars after all. I've seen a couple of the 'good' Polanski movies and did not much care for them, so my uninterest and the additional moral reasons provide an incentive not to attempt a new film that garners good reviews. This is not incidental, since I consider periodically revisiting things I have disliked in the past to be one of my responsibilities as a consumer of culture. The moral judgments themselves I am also comfortable with: if Woody Allen did what is alleged, he deserves a mark against him.
(A theological aside: I am uncomfortable with this even as I acknowledge my attitude about it. I think I am bound to hope for his redemption and to believe in its possibility, so even while maintaining my moral judgment I think I must also accept that one day I might need to transcend it, and let it go. And accept the possibility that this might come about without my ever being aware of it.)
There are also relevant economic angles and authorship questions along the lines of "A Woody Allen film or one he co-wrote and directed and which a bunch of other people made critical aesthetic contributions to?" and "Scott Fitzgerald or Fitzgerald and Maxwell Perkins?", but this post is too long as it is.