It is because formal justice requires 'consistency' the judiciary are obliged to follow the doctrines of 'staire decisis' and 'ratio decidendi' which means they must respect and follow decisions or court authorities of other judges at the same level or higher courts.
However sometimes Case Laws build up on the back of an assumption made in a previous precedent, like a house of cards.
It was Sir Roualeyn Cumming-Bruce who referred to 'children of tender years',
'Ithas also been said that it is not a principle but a matter ofobservation of human nature in the case of upbringing of children oftender years,that given the normal commitment of a father to support the family, the mother, for practical and emotional reasons, isusually the right person to bring up the children.'(Per Sir RoualeynCumming-Bruce in Re H (a minor)1 FLR 51, CA.1990)
'At the risk of being told by academics hereafter that my views are contrary to well-established authority, I think that there is a rebuttable presumption of fact that the best interest of a baby are best served by being with its mother, and I stress the word 'baby'. When we are moving on to whatever age it may be appropriate to describe the baby as having become a child, different considerations may well apply. But, as far as babies are concerned, the starting-point is,I think, that it should be with its mother.'
Yet if 'bonding' does not occur, fathers face the risk of losing contact altogether because of the court authority set by Sir Stephen Brown, 'The welfare officer, together with the justices, did not pay sufficient attention to the fact that there was no bond between the natural father and the child.'
The judiciary can also argue that fathers who reject contact orders because they are insufficient to maintain a meaningful relationship, do so because they do not want to see their children by choice and are 'vexatious'.
In the House of Lords debate on the proposed Shared Parenting legislation Lord McNally said (16 October 2013 : Column GC282),
The noble and learned Baroness, Lady Butler-Sloss, from her vast experience, claims that the way it is worded produces a contradiction. Let me try to explain our approach to see whether we can convince her, but I suspect that we will be coming back to this issue on Report. It is not possible for the presumption to clash with the paramountcy principle. The paramountcy principle is not a rebuttable presumption. The child’s welfare must be the court’s paramount consideration. If the court does not believe that the child’s welfare is served by the involvement of a parent, it will not order any such involvement, and the clause does not require it to do so. We are not saying that the court must make an order that involves both parents, nor are we seeking to define the nature of the involvement which the court may order. We are certainly not making any assumption about how the child’s time may be divided. That is not what the clause is about.