First of all, yes. This episode is very much filler. They could've made this a 10 minute opener for the finale as is and nothing would've been lost. It gives a smidge of insight into the man in the black hat, but that insight is stereotypical evil/is cursed.
Also, regarding the claims of it being anti-Christian, that's literally the opposite of what's happening. It's made clear when the boy speaks that it's the Devil/demons/whatever manipulating the man in the black hat under the guise of God. He literally says that he answered Epps when the Lord ignored him. The lady said if God saw how Epps was misusing the Word, it would burst into flames...and then it bursts into flames right there in his hands. You could only think this was anti-Christian if you skipped the entire second half of the episode.
Also, regarding the claims of it being anti-Christian, that's literally the opposite of what's happening. It's made clear when the boy speaks that it's the Devil/demons/whatever manipulating the man in the black hat under the guise of God. He literally says that he answered Epps when the Lord ignored him. The lady said if God saw how Epps was misusing the Word, it would burst into flames...and then it bursts into flames right there in his hands. You could only think this was anti-Christian if you skipped the entire second half of the episode.