I don't know what the nazis thought (or think) about Atlantis, but who cares? If it ever existed, and Graham is 100% correct, how is that fact not infinitely more interesting than what race they were? I certainly don't think about my own ancestors, which were verifiably "uncivilized" up until the 13th century AD, as being lesser than anyone else.
He's clearly wrong, and it's easy to discredit him scientifically. Why not do that instead of playing the race card? Everything's a nail when you have a hammer I guess.