I don't trust people who constantly brag about how nonpartisan they are. I think O'Reilly chooses his opinions based upon making himself appear independent more than he does upon principal. (That in addition to the fact that he's a doofus...)
I'm not sure that you can ever say that Independents, moderates or middle-of-the-roaders ever take a stance based on principal. That's kind of an oxymoron.