Indoctrination rarely has any lasting impact on a child into adulthood...if it did then we would all still be deeply pious....
The problem is that what you are suggesting is effectively excluding a families children from what is to some Parents a fundamental part of their live's, both individually and as a family unit.
Judaism in particular is not simply a religion, it is an integral part of a Jews cultural and ethnic identity and to a lesser extent this is true of Christians also....to fully shield children from religious influence you would have to remove any and all reference to religion, including all the cultural references that inform and are integral to our cultural identity....such as Christmas, Easter, and so on...