And if you're one of those people that cares about the publicly expressed political views of an author you may want to go check out akiko's post about him, or you could just go check out the original
I can kind of sympathize with the people who say you should judge art by the qualities of the art itself, and not by the opinions of the artist. It's a noble attitude, in theory. In practice however i think it's quite reasonable to make exceptions. The most obvious case is when opinions you find odious get expressed in the art itself. If they're going to make their views a part of the art it's entirely fair to judge them on those views. I think it's also fair to boycott the art if the artist is using either the money or the fame they've achieved by that art as a platform to loudly express views you disagree with.
But really i think it's fine to avoid works by a particular artist for any reason you feel like. As i kind of alluded to in my post about ghetto/non-ghetto SF, a lot of people feel some kind of emotional attachment to the creators of works they like. On the one hand this can increase your enjoyment of the works in question, but on the downside if your view of the artist is ever tarnished it can reflect on your opinions of the art itself. This may or may not be reasonable from a strictly logical point of view, but it's entirely human. If the artist says they don't want to be considered part of your favorite genre, or if they treat you rudely at a con, or they express political views that you vehemently disagree with, then you may have trouble looking at them or their work the same way as you did before.
Of course this is all quite a bit easier if the artist is "kind" enough to do so before you've read any of their work. It's so much easier to boycott something you haven't developed a taste for yet :)