I really enjoyed the story line and appreciated how the game is open world, but also forces the player to be a fated character and follow a very linear story line, which ultimately the player has no control over.
Most of the news stories and comments I read from players who don't like the ending are also misunderstanding the story. One PC Gamer https://www.pcgamer.com/far-cry-5-ending-discussion/ article began with the criticism that the cult doesn't explain it's beliefs enough throughout the game. The author specifically mentioned a lack of cult music and claimed the only song they sang was "Amazing Grace".
"All their covers of Amazing Grace don't spell out what they believe in besides a vague dissatisfaction with the state of the US government and the character of the American people. It’s not until just before the credits roll that the cult’s purpose starts to take shape, a bit too late for recruiting purposes."
So, somehow the author of the article must have played through the entire game and not heard the many instances of the cult's song, "When the world dies into the flame, we will rise again!" playing on nearly every radio. And then he wrote an article about how the game isn't great because he didn't notice that it contained the elements that he thought would have made it a better game. The cultists even say many things to themselves if you listen to them when they don't know you're around, some of them question whether all of the murder they're committing will be worth it, for example. I just mean, this author of a major gaming magazine wrote an article about how the game doesn't contain enough back story, but the game itself (not the cut-scenes) tell the majority of the story, especially through explaining the varying motives of the cult members.
Most importantly, the cult believes that Armageddon will happen soon, and the beginning of Armageddon will be signaled to the cult when law enforcement attempt to arrest their leader, Joseph Seed. This belief is then made inevitable by the 3 options of the game. In the beginning of the game you may either arrest or not arrest Joseph Seed, either signaling the beginning of Armageddon yourself, or choosing to wait until you have more backup; at which time Armegeddon will begin when the backup arrives to arrest Joseph Seed. Then at the end of the game you get the same choice again, to attempt arresting Joseph Seed now or to go back to Missoula for reinforcements. If you choose to arrest Joseph Seed at that time in the game you are opening the final seal and Armageddon begins; if not, then you are just postponing Armageddon until reinforcements return to arrest Joseph Seed.
Since the cult believes in an impending Armageddon, they also believe the only way to survive will be in one of the cult's bunkers (which is kind of ridiculous given that 90% of the properties in the game have personal fallout shelters but that's a side note. On a related side note I'm hoping to see Eden's Gate as a faction in the next Fallout game...) The cult genuinely believes that it's saving everyone who's "worthy" of surviving Armageddon. And in the game's world, they ARE doing that, subject only to a conversation about what standards they use to determine who's worthy.
And for the most part, even the non-cult NPC's in the game world all know these basic beliefs that the cult has. One soldier-for-hire said during gameplay, "I'd rather die in the apocalypse than take shelter in John's bunker..." and Merle goes on a tangent in the helicopter after you rescue him from the cult about how they said they were "saving him" when they ambushed him.
Far Cry 5: The Unofficial is a linear playthrough of the main story missions, edited like an animated series. The HUD is turned off, the player/main character never dies or goes aimlessly wandering away from the plot, and all of the character maintenance and loading screens are edited out for continuity.
Episode 1 is available here: https://youtu.be/Bw-r3soxBl8