Pathos is arguably the most potent of all rhetorical appeals. It is also the most versatile, as it can appeal to emotions, imagination, morality (often confused with ethos). Elmer Gantry employs this device primarily through imagination.
A common goal and wish for skeptics is to be able to prove that their opposers are false. Many skeptics claim that religion and similar factions are simply schemes and cons. This film clearly feature a con couple. It allows opposers to the religious movements of the 20th Century to bask in a movie that portrays such sentiments. An issue with doing this is that it may create a confirmation bias with users, as they may erroneously claim, "all of these religions are false, this movie clearly shows that!" The extreme nature of the characters in the film as utilize fear and other emotions to help sell the idea that cults are a dangerous element of society.