Does the artist's sin spoil the art?

Is it possible to celebrate the work or art of somebody who has committed a terrible sin?

I think most of us would agree that being a sinner doesn't disqualify you from being a good artist—if it did, there would be no art to appreciate at all. But when somebody goes seriously astray, does it retroactively taint the good work they've done in the past? Take the example of a convicted child molester who also happened to be a highly respected music teacher and author:

To some within the music fraternity, there are two Brian Daveys.

One a devious paedophile jailed last year for sexually abusing girls as young as four. The other was a respected music teacher who wrote books on the recorder that many tutors regard as among the best textbooks for children. [...]

Can you value work produced by someone whose private life and acts you find appalling? Do the proclivities of those responsible for artistic or intellectual works have to be taken into account in their appreciation?

It's one thing to create art and be a sinner at the same time; but it gets more uncomfortable when there is a link of some sort between the art you create and the sin you commit.

The Brian Davey situation is a pretty extreme example, but I can think of more mundane, but equally serious, questions. For instance, could you listen to worship music performed by somebody whose personal life was a stark contrast to the values in the music? Would you read a well-regarded Bible study, sermon, or devotional by somebody who later abandoned their faith? There have been more than a few high-profile Christian writers and leaders who have jettisoned their faith after writing lots of good Christian material. In a case like that, do you appreciate the work anyway, drawing what good you can from it—or does your knowledge of the author's moral failings make it too difficult to celebrate their work?