The criticisms of the methodology are valid.
Another factor to consider is that there is a strong genetic component for religiosity. Children in religious households are likely to have inherited those genes which may also account for their 'sensitivity to justice'.
In other words it's not the child-rearing and religious indoctrination that affects the child's personality but their genetic inheritance.
On the other hand, teaching children that the world divides into 'them and us' does not contribute positively to their social development.