Does the movie even mention God? I took it to be more of a cosmic event. Like nature or the universe requiring humans to sacrifice themselves as an act of pure love to justify the continuation of the human race, which is otherwise destructive.

The "four horsemen" surrogates say that families have been forced to make a sacrifice for generations, and that their visions only brought them to the cabin, and didn't show them who would be in it. So it's not personal for them. They're following the instructions they've been given.

Weird that you think it's propaganda just because it's got a gay married couple as the protagonists. Not sure what you're implying here. Would your response to the subject matter have been different if it had been about a straight couple?