With pop music the singer/song writer typically is the character/narrator in the song, or shares the beliefs of the character.

Do you think novelists do the same thing (Philip Roth doesn't believe in God, therefore his central characters don't, either), or do they strive to create characters they would disagree with, regarding religion, tastes, opinions, beliefs?

I think most writers write what they know about. Philip Roth doesn't write gang related ultra violent hip hop free verse poetry, for instance. But do these creations share his beliefs? Can writers loath and despise their narrators?

I am only about 1/3 through "The Tin Drum" but it sure looks like Grass does not care much for his narrator, Oskar. If it turns out that Oskar is a stand-in for Nazi Germany then for sure the author doesn't like him. I doubt the relationship between author and narrator will be that simple though.

Authors experiences and beliefs must enter into their work, whether they're writing pro or con any given subject matter. I don't see how anyone could completely avoid being influenced by their life and have those influences show up in their work.

As for the Tin Drum, I don't see how anyone (the author included) could like Oskar.

Perhaps if the writer writes a "detached" piece, say Zombie by Joyce Carol Oates. Of couse, she doesn't believe a single thing a serial killer has do say.

"Detached" is a good description of how an author could accomplish this. I think this requires a very accomplished author, like Oates, and a lot of research.
I've read a lot of Oates work but not Zombie. I'm going to have to pick it up.

If you have read the Woman's Murder Club James Patterson books and see that James Patterson is neither a woman, nor a seriel killer you can see that some authors have an imagination beyond our belief.
Many authors can ONLY write about what they know. For Philip Roth, he doesn't believe in God, so he can only write about "There is no God" books. If he had a creative mind and could THINK that there might be a God, he could write a book with the character a strong believer.
I think that if an author has an imagination beyond our comprehension, then they can have their character believe in whatever and the author doesn't have to believe their own words. ~To me: that's what makes authors amazing!

I really hoped that made any kind of sense.

Yes, it did make sense. Thanks for your thoughts.

Good question.

I think that an author's opposition to his or her narrator depends on the character's narrative stance.

If an author's main character employs a wide narrative stance (interacting with an array of characters in the text), the author can easily "distance" himself from the main character and make that character totally different from the author.

However, if the main character is introverted (whereas most of the narration on the main character's behalf is internal), the author will have more trouble making the character three-dimensional. The further into the mind of the main character the author goes, the more similar it will be to the author's mind.

So yes, an author can hate his narrator. But it gets harder the more in-depth the narrator is.

Yes, you can dislike your narrator, but honestly, why would you want to? When I'm writing, I spend every waking moment (and sometimes unconscious moment) in my narrator's head. Your love of your characters shows in your writing, so even if your narrator is scum, he should be loveable scum to you.