That is the implications because the Atlantis myth has become white supremacy through deeply racist works from Helena Blavatsky and Ignatius Donnelly. Spoiler: the Nazis were really into this stuff.
It boils down to that that all the non white peoples could not have done any of these things and needed help from a superior white race, robbing these peoples from their own ingenuity and heritage.
Just because he isn't an outright racist doesn't mean that his theories imply that. I've not read his books but from what I've seen he likes to quote works built on the authors above that are just as racist.