Chapter 5 repeatedly treats True Parents as the point where divided realities can meet. They are not merely one more authority inside history, but the axis through which God, the physical world, and the spirit world can finally come into one ordered relationship.
That is why the chapter gives them more than symbolic importance. Without a living axis, the two worlds remain fragmented into parallel realms, each lacking a center the other can recognize.
The claim also explains why attendance to True Parents is described in such high terms. To bond with the axis is to enter the possibility of shared order rather than private religion.