The profound bonds between the members of a family.
How, without a church, greed and violence come to rule unchecked.
The necessity for the values of Western civilization.
The abomination of sacrifice of the innocent.
The need to value the aging when they are past their usefulness.
The requirement that freedom be defended--that righteousness does not mean lying down like a doormat.
The sinfulness of singling someone out for ridicule (Blunt, who is the brunt of everyone's practical jokes).
The scene where the village elder tells a story, of how man has an empty place inside him that can never be filled. A Christian would say it was a Jesus-shaped space and that it can be filled. But there are no Christians there, ergo no one to tell people how to fill up that space. The elder went as far as he could go with his wisdom.
There's probably a lot more too.
Yes, I saw the main theme of the movie as a conflict between a tribe of people who loved life versus a society that was spiraling into a death cult.
You have some good points, everything you mention is present.