Most of the time, human guidance occurs before the AI generates anything. For example, ChatGPT was trained with human involvement, but most of what it writes will not be reviewed and edited by a human.
However, an identifiable component of the text must have been written by a human author in order to claim copyright. So most of what ChatGPT writes cannot be copyrighted. It would only be eligible for copyright if a human reviewed and edited what ChatGPT had written.
There is an underlying tension in that copyright is explicitly meant to be an incentive for creative efforts made by humans (who would otherwise be doing something else), and AI is generally designed to replace humans engaged in creative efforts.