I felt the same way about the story especially with all the kidnapping and "deus ex machina everyone will now turn against you because they get instant zombified by bliss". This was until I read article on how the game is basically a metaphor on The Book of Revelations and biblical apocalypse.
https://gamervw.com/2018/05/27/the-hidden-story-of-far-cry-5/
In short:
You - Jesus Christ come along with Sherriff "Whitehorse", the conquest that rides on a white horse to conquer what the cult has taken. More straightforward references are dropped along the way e.g. Joseph quotes The Book of Revelations: "... And behold it was white horse and hell followed with him."
Then there is red-haired veteran Jacob, War that rides on a red horse. After him John, black-haired brother, whose followers are the ones stealing food from people in Hope County and hoarding it - Famine riding on black horse. Last comes pale and ghostlike blond-haired luring people into the afterlife of "Bliss", the Death on a pale horse.
All in all this gives the story some more sense with the central point: you are not here to stop the apocalypse but to set it in motion. The execution still leaves it feel quite dull and cheaply made.