He thinks all non-european accomplishments came from the heavens and takes oral folklore as definitive proof of how history went down. He's a pseudo-science hack.

Oh no, he has very much earned his reputation as pseudohistorical hack with his terrible research methodology, heavy reliance on old, outdated, and often plain bad secondary sources without doing even basic checks. (For instance, are they even reading the maps they're working with?), and his blatant mischaracterization of the field and studies.

Of course, Graham's explanation for why anyone knowledgeable in the field immediately calls him out for his flagrant and basic mistakes is that they must be in cahoots instead of his "research" being terrible.