Is it really true that children are so easily indoctrinated? In my experience there is a decent probability that they rebel against whatever the dominant ideology is when they are growing up once they enter puberty.
It certainly is. You can easily single out rebellious children under a certain doctrine. You can reduce the numbers just by punishment. They might still be rebellious afterwards, but they are also isolated in society as a result also adding to the spiral.
It is hard to deconstruct the frame you are living in.
I'd say kids are both malleable and at the same time grow to be incredibly resilient.
I personally do not have kids.