The film and the book are a big "what if??" - they explore a non-reality, an imaginative little conspiracy theory, and they suggest that the church is responsible for the biggest cover up in human history - just sounds like a sensationalised tale to me. The ideas in it postulate a situation where the church is secretive, but its for suspense value, its a literary device.
What you're failing to recognize is the fact that the protestant agenda has always attempted to make the Church seem secretive and manipulative. And, the film and book are not a "big 'what if'" nor is that how Dan Brown attempts to present them. By listing his page of "facts," wherein he cites faulty sources, and then further by blatantly misrepresenting actual religions and groups, Dan Brown is clearly attempting to manipulate his audience. Remember, the website for the film was SODARKTHECONOFMAN...Not WHATIFTHECONOFMAN?.
Most high school history students in australia at some point do a case study of the JFK assassination. most people don't believe it was lee harvey oswald, and many suggest a huge US government coverup. Does that make these ordinary australians who eat their mcdonalds and watch american sitcoms anti-american?
While I'm not sure that paranoia is necessarily the best mentality to encourage in the public school setting, it does not make them anti-American. There are two reasons why this analogy doesn't hold water. One is that you are comparing ONE SMALL EVENT potentially perpetrated by the American government to the FOUNDATION of a religion (and many other religions that sprang forth from it). If they were saying that the US Government's consititution was based on a lie, and presented a list of "facts" in an effort to manipulate the general international population into believing that, then I would say that, yes, they were anti-American.
Secondly, a government is a government. Religion is a different matter. Religion is sacred and should be treated as such.
I still maintain that the davinci code has provoked one of the biggest mass-overreactions i've ever witnessed.
And yet, the numbers speak differently, don't they? It's been proven that this type of film shakes the faith of the weak. We are indeed the keepers of our brethren, and when something like this shows up, it is not overreaction to say, wait a minute folks, and expose all the holes. It's okay to say, "You know what? This is an attack on our religion and that's not cool." Nobody would stand for a film that so blatantly attacked any other religion, would they? Why should we say that it's ok when the target is God's Church?