Selective exposure does happen? What an interesting phrase. It sounds almost like it's a rare, rare thing. Oh chill it man, it happens so very occasionally. Here, let me pour you some tea.
You miss the point. I maintain that epistemic partisanship, or if you like selectve exposure is the rule. Not the exception. And you think I'm only talking about those mentally benighted Christers. No. I'm speaking of the common run of men, faithful or godless, liberal or conservative, utilitarian or Objectivist. I speak of human motives. Not ideology. John Stuart Mill counseled against this blindness by suggesting in his autobiography that a man who wants to get at the truth should seek to argue both sides of a motion with as much zeal as a partisan. This ideal is seldom met. Not by me. And not, if my observation of people proves correct, by others.
You missed the rest of my post. You are attributing a peripheral theorem of attitudinal change as a large determiner of a person's change in behavior and attitudes. It isn't. The central theorem has validity as well and neither is a complete explanation of why people's beliefs, attitudes, and behaviors change. Like I said your conceptual map has merit, but isn't complete.