This film is neither anti- nor pro-ANYTHING. *spoilers*
It's really amazing how ideological these threads are.
Why are people questioning whether the movie were real--as in, really happening in Sharon's world and not merely in her mind?
When you watch Lord of the Rings, do you question Frodo's sanity because tall gray wizards simply can't blow ship-shaped smoke rings in real life?
No. You suspend your disbelief and accept the premise that the writer and director provide as you watch the film.
In the case of The Rapture, we're given a scenario in which God exists, where prophets all over the world--including one referred to as "the boy" that happens to be geographically close to our protagonist Sharon--warn of the earth's impending judgment, and Christians (those chosen to be Raptured) experience visions of a pearl letting them know that the kingdom of God is at hand.
Whether you believe this in real life or not should have nothing to do with whether you're able to accept this as part of the film's diegesis.
Debates about whether this film is pro-Christianity, anti-Christianity, pro-religion, anti-religion, pro-fundamentalism, anti-fundamentalism, "real" or Sharon's fantasy, about a fringe cult vs mainstream thus "true" Christianity, are not only beside the point, but distracting from more interesting discussions regarding the weightier themes that this film tries to tackle.
The writer/director deals with Sharon's religious conversion with pathos and depth. Even though I do agree with another thread on this board that the pacing of this film could have been better, we see where Sharon came from, her life at the crossroads, even her 'honeymoon phase' as a new convert, and her later disappointment and irreparable anger at God. Never do we get the sense that the writer is mocking, or even critiquing, the religious--except perhaps in the scene where Sharon goes to jail and encounters the girl with the pearl tattoo. The girl's naive optimism, her "just world" worldview, and simplistic consideration of her religion as nothing more than good vibes and a recipe for entrance to heaven, reads as a kind of shallow faith as opposed to Sharon's: a true Abraham whose devotion to God has only been met with the worst kind of suffering.
Incidentally, for those of you who are unfamiliar with the story of Abraham, God asks him to sacrifice his son Isaac even though God previously tells Abraham that his offspring will be as numerous as the stars in heaven and the sands of the earth. Now, imagine Abraham's anguish: not only as a father about to sacrifice his son to God, but also trying to wrap his mind around the ABSURDITY of it! How can God promise that Abraham's offspring will populate the earth, yet request of Abraham the very thing that would invalidate that promise? And how could Abraham carry out this command--how could he worship a God that commands of Abraham that which invalidates his own worthiness of worship?
Abraham doesn't actually have to go through with it, though; right as he's about to slit Isaac's throat on the sacrifice altar, God stays his hand. Sharon, however, is more hardcore. Out of pride, presuming to know the mind of God, of attempting to force God's hand and meet him halfway, she takes her daughter into the wilderness to await their Rapture. And yet also, out of mercy, to end her daughter's earthly suffering, Sharon kills her, to do what she could to fulfill the promise that Sharon felt God had made to her but broke--and this time, God stands by silently and lets it happen. There's a tragic heroism in what Sharon does: despite her flaw of pride there is her total devotion. And unlike Abraham, she actually has to pay the price for what she's done.
Sharon has every right to be angry with God: a God who permits the senseless murder of her husband; a God who leaves her desolate and alone, who makes her suffer and, even more cruelly, demands her love nonetheless; a God who offers eternal salvation, like a cookie, in exchange for Sharon's overlooking of what she's had to endure.
The film is about Christianity, yes. But it's not necessarily anti-Christianity, or pro-Christianity. While one could certainly argue that because the film adopts Christianity so completely in the figure of Sharon that it only makes the final outcome that much more of a devastating critique, I think it's more even-handed to say that it wrestles with Christianity. It gives it serious and deep consideration, more than most Christians give their own faith. And I think this is the most important thing to consider. Someone in another thread mentioned that this film came out during the rise of evangelicalism in American politics. When we contrast Sharon's conversion and devotion and wrestling with her own faith with her jail cellmate's naive, sheltered, "thin religiosity," perhaps this is Michael Tolkin's way of challenging everyday, comfortable Christians with these philosophical aspects of their faith that they simply leave unexplored. Yet at the same time, throughout the film, Tolkin treats Christians with compassion, empathy--even at times awe--enough to make nonbelievers at least consider what it is to have this form of religious experience.
The film asks us to imagine that Christianity is absolutely the one true religion and that eternal salvation is not only possible but available to anyone. But it also forces us to consider at what cost. Sharon is, after all, the film's most devoted Christian. And yet, she is also the only person in the world with the moral courage to stand defiantly against the arbitrary rules that let murderers and Johnny-come-lately park rangers and tattooed mall evangelists and presumably every other hearing, rational person that anticipated that sixth trumpet into heaven. The film's most devoted Christian is denied eternal salvation.
The reason people have so much difficulty classifying the movie's political alignment is that it doesn't really have one; it's better than that. Yes, it's a Camusian, existential film about suffering and meaning, but I think it does one better than that too. The Rapture is not so much political as it is philosophical--or, more correctly, it teaches us to be philosophical about our politics. It requires us to plumb spiritual depths and examine universal questions, but also consider ourselves doing so--if Sharon is truly just in defying God and his seeming injustice, then where does my belief in her justice come from, and why do I feel it so strongly? Can Christian faith truly be reducible to a set of arbitrary rules--and if so, what's to say that the secular rules I follow aren't just as arbitrary, although I feel them with equal conviction? It's a film that short-circuits our desire to resort to easy positions, and hopefully makes us abandon our binary mode of thinking--whether as anti-Christian or pro-Christian--as both have identical tendencies to view an "us" as in the right and a "them" as in the wrong.