Are you telling me that adults do not intentionally mislead children to believe that Santa Claus literally exists, or that many children who are so misinformed by their parents do not believe, as a matter of literal fact, that a magic man in a red suit lives at the North Pole and brings them toys via flying reindeer on Christmas morning? Or that you see no important difference between that literal belief and the experience of, say, going to see a Disney movie where the children understand that what's happening is just a story and the parents make no effort to persuade them otherwise?
ETA: Does your answer change if we replace "Santa Claus" with "Jesus"?
Yes.
Adults create a fantasy in which they get their kids to join in with the make believe. It is called playing, having fun, make believe and so on. What on earth do you think playing and make believe is?
And I am struggling to see how "Jesus" can be squeezed into this discussion?