The continued debate reveals traditional Lamanite beliefs about the Nephites. As an incarnation of the Great Spirit worshipped by the Nephites (however the Lamanites construed the character of that god), Ammon would logically intend harm to the Nephites’ hereditary enemies. Was not Lamoni’s household lying as if dead evidence?
Redaction: This colorful discourse seems to be so favorable to Nephite beliefs that I suspect that it is Mormon’s addition to the story. This “conversation” occurs while Ammon is unconscious. Ammon could not have accurately recorded it. The authentic scene would certainly have contained debate, but this particular dialogue was likely constructed later.