Here's an excerpt from Donald Miller's blog on this topic:
So here is what I surmised: American culture has become a consumer culture, and a large demographic within the culture simply does exactly what they are told, as long as what they are told promises a pay off of some sort.
They do not ask questions. They trust you if you seem trustworthy. Many evangelical leaders, then, simply become info-mercial-type salesman, selling their understanding of the truth to this large demographic. Most of them are extremely well intentioned, and do remarkable ministry around the world for the poor.
The dumbing down of what we must loosely call truth is just a sign of the times.
Of course there aren't any Christians who would claim to be the dumbest. But it's not only evangelical Christians that are dumb. Is it possible that you are a dumb American if you do what you are told in the hopes of some sort of pay off? Pick a health magazine. Pick a get-rich-quick book. Pick the better-sex-column on a website.
The definition of dumb is the obsession with guaranteed pay off. This is especially dumb when it is pursued at the expense of character, integrity, sacrifice, and truth.
Here's the link to Miller's entire blogpost.