[Cicero]

Picasso was extremely talented and powerful. But much of his later work is cruel and brutal. In particular, he is noticeably brutal toward the women he paints. Some terms that come to mind are deconstruction, rape, and debasement. So the question is, can a painter be great if he is technically sophisticated and emotionally powerful but morally debased?

I don't think so, but then I'm in the minority on this one.

[dighton]

An Orwell essay addresses your question:

... the worst crimes are not always the punishable ones. By encouraging necrophilic reveries one probably does quite as much harm as by, say, picking pockets at the races. One ought to be able to hold in one’s head simultaneously the two facts that Dali is a good draughtsman and a disgusting human being. The one does not invalidate or, in a sense, affect the other. The first thing that we demand of a wall is that it shall stand up. If it stands up, it is a good wall, and the question of what purpose it serves is separable from that. And yet even the best wall in the world deserves to be pulled down if it surrounds a concentration camp. In the same way it should be possible to say, “This is a good book or a good picture, and it ought to be burned by the public hangman.” Unless one can say that, at least in imagination, one is shirking the implications of the fact that an artist is also a citizen and a human being.

-- Benefit of Clergy: Some Notes on Salvador Dali.