We lie to children all the time to protect them. Reality isn't actually good to be exposed to when you are a child; it's much better to encounter it in a safer,

We lie to children all the time to protect them. Reality isn't actually good to be exposed to when you are a child; it's much better to encounter it in a safer, nonthreatening way, which is why we have euphemisms and hide the fact of death and (extreme) evil for so long. All of that however is separate from whether we should teach religion, which is more or less orthogonal to objective reality. Religion covers that which is unobservable, almost by definition.