Dion Fortune was wrong.
Not all goddesses are one goddess.
There's Earth, Mother of all Life. She and her family—Sun, Thunder, Fire, the Winds, the plants, the animals—live out our lives together. Her story—our story—is what we call the Wheel of the Year.
And then there's the Moon.
Moon is the wayward daughter, the child who goes off and has a life of her own.
She has her own cycles, but they're not synched with those of everyone else. She has her own changes, powerful and independent. She's still Earth's daughter, part of the great family of the gods, and part of the life of that family, but very much on her own terms.
There in her sky (L. M. Boston) she wheels, independent of Earth's cycles, wandering the horizon in her Great Cycle as she will: ours but always her own.
That's why we worship her.