Why do the tribal cult followers say they came to the woods in Chapter 24? What do they reveal about Deedee?

One woman in the cult group tells Mark that they left their village to seek holier places following the rain of demons from the sky, and that the spirits speak, and she and the others follow their orders. The woman says that Deedee is evil, and has brought the evil on them all. Mark tries to reason with the woman and the others, but she will not reason.