> you ask some parents about santa clause. they say we are athiests, but we pretend to believe in santa clause to make our child happy. then you ask the child about santa clause, and they say i pretend to believe to make my parents happy.
I think it descends from a line about labor in the USSR: "We pretend to work, and they pretend to pay us." Tony Judt in "Thinking the Twentieth Century" had a line about Moscow needing its satellite states to avoid loudly or conspicuously disagreeing with party ideology even if in practice they were able to diverge. "You pretend to believe and we'll pretend to believe you."
At higher levels of simulacra, the statements people make are less about reality, and more about what they want people to believe they believe about reality.
While some kids may become very vocal about it when they suddenly stop believing in Santa Claus as a literal being, they children (and adults) can continue enjoying him for as long as they're not embarrased by it.
Having a small child in the family believing (or pretending to believe) can be a way for everyone else to enjoy him. And some families continue to have him even when nobody believes.
The same is sometimes true about religions. People can continue to value them even if they stop believing in the literal Sky-Father.
I can see how Santa Claus can live as a fairy tale, with small kids playing with the idea of the entire thing being somehow real, the same way as Goldilocks or Bambi. This is indeed cute, unless taken too seriously.
It's quite a bit harder with religions: they are not a once-a-year pleasantry, but are things that shape your entire view of the world and the way of life. A faintest idea that they are but a cute tale is literally a destruction of a worldview, a catastrophe instead of a mild disappointment. Knowing, say, Christianity or Islam as a cute tale only works for people who never were believers.
Belief comes at many levels of intensity. People with low intensity beliefs can drift away without experiencing a world view collapse.
There are certainly people of most religious backgrounds that continue to practice and enjoy many of the religious traditions and practices even generations after they stop believing in the supernatural parts.
-- Upton Sinclair (?)
This is how it works for the child and Santa.