The problem is, of course, that writers are people. And people are different from other people. They have different beliefs, vote for different candidates and have different levels of tolerance for those who, in turn, are different from them.
The other day, a writer was posting telling everyone NOT to buy Orson Scott Card's books. It appears this writer, a man, likes putting his genitals into other men. OSC is a member of a religion where that kind of thing is frowned upon. Ergo, in his works "If you're gay and buying Orson Scott Card's books, you're supporting repression."
Now this is not an issue of avoiding a book because of subject matter. No one likes to be preached at. I tend to avoid books with a heavy-handed dialectic even if I happen to agree with the author (which isn't often). No, this is someone calling for the shunning of a writer because of their religious beliefs.
The opposite happens as well. Openly gay or Republican or whatever writers will be shunned, not for their books but for who they are.
My question is, should we separate art from the artist? Richard Wagner was, to most people, a loathsome human being but man he wrote some good music. Modern day, there are lots of musicians I'll listen two that I wouldn't trust with my sister or my house or my bathroom for that matter.
You can make a case that the character of an artist is relevant for non-fiction or memoir. But should we take the artist into consideration for fiction as well? If someone snorts cocaine or cheats on their spouse or worships Shub Niggurath, the Black Goat of the Forest with a Thousand Young does that matter if they're writing about made up worlds and made up people?
It's a free country, mostly, and we certainly shouldn't be forcing anyone to buy anything they don't want to. Though, if you're in school, yes you will be 'forced' to read authors you might not otherwise prefer. But once you're out in the big, bad world, you're going to be exposed to all different types of beliefs.