Why do a majority of parents troll religion on their children when...?

the child, especially under 10 years would most likely not understand a bit of the religion. Since the child brain is still growing and that they are highly gullible they'd believe anything without proof, sorta like telling them 2 and 2 IS 4, that's how it works, theres not other way. I don't understand this...they're polluting the child's mind with nonsense and blasphemy, not exactly what I'd call fabulous parenting skills...