The linked document labeled "Part 2: Copyrightability", section V. "Conclusions" states the following:

> the Copyright Office concludes that existing legal doctrines are adequate and appropriate to resolve questions of copyrightability. Copyright law has long adapted to new technology and can enable case-by- case determinations as to whether AI-generated outputs reflect sufficient human contribution to warrant copyright protection. As described above, in many circumstances these outputs will be copyrightable in whole or in part—where AI is used as a tool, and where a human has been able to determine the expressive elements they contain. Prompts alone, however, at this stage are unlikely to satisfy those requirements.

So the TL;DR basically implies pure slop within the current guidelines outlined in conclusions is NOT copyrightable. However collaboration with an AI copyrightability is determined on a case by case basis. I will preface this all with the standard IANAL, I could be wrong etc, but with the concluding language using "unlikely" copyrightable for slop it sounds less cut and dry than you imply.