Then how come every scary movie with vampires or demons possessing someone (like the movie I watched last night) has people in trouble with the devil and they always want a priest? Huh?
I've seen a lot of such movies and never, never has one person ever shouted out "get me a good Bible-based non-denominationl preacher." No, it's always priests and Holy Water and Crosses. :-)
Seriously though, possession is real and so is exorcism. And it is, of course, the power and faith in Christ of the exorcist that does the job. But the holy items help. They are battle tested. The movie "The Exorcist" was based on the story of a little boy in Maryland. His parents took him to see his pastor, a Lutheran. The pastor told the family "better go to the Catholics, they know how to deal with this."
SD
1) It establishes that the speaker is an expert on both Fundamentalism and obscure things like Gnosticism
This is a little cynical, bass. Yes it does establish that the speaker has some knowledge of past heresies in church history. Since accurate history is so sorely lacking in most fundmentalists it is a good point.
2) It compares the enemy (Protestantism) to a group all acknowledge as heretics (even Fundamentalists, hmmm)
You haven't met the Fundamentalists I have here then? Most will not acknowledge proven heresies as such, preferring to think of them only as cudgels Catholics use to beat people with. They usually refuse to enter into the theoretical discussion needed to understand such heresies. Some are truly "agnostic" about such issues, others just don't wish to agree with Catholic terminology. Consider how hard it is to get fundamentalists to answer questions like "is Jesus God?"
3) It points out the role of the doctrine of the Catholic church and its infinite superiority as it beat back the gnostics once and will do it again
I think you mean this cynically, but you are correct nonetheless. Do you not agree that many today hold the same position as heretics of old?
SD
Hollywood goes in for image over substance. The world has no idea about the spiritual. Neither does catholicism. Jesus and the Apostles used the authority of the Father - not tokens, crosses and 'holy' water which have no power over a single demon. Faith doesn't make a symbol work. And invocation of symbols rather than the authority of God.. Witches call them "spell components" or "familiar" items.