Divorce court judges who deny a child's right to free and equal association with both fit parents are acting in the divorce court's best interests.
The best interests of the child standard is the most powerful basis for arbitrary and capricious discrimination the family law system has ever seen.
A fit parent's interest in equal custody & companionship with their child simply outweighs the state's parens patriae interests even in divorce.
To learn who rules over you simply find out who you are not allowed to criticize.