Moriarty (hmmm) is saying that paper gold gets ahead of physical gold at tops due to overexuberance bringing in more paper players which makes sense, and at bottoms physical gold (strong hands) gets ahead of paper gold (speculators) which has a lower XAU/Gold ratio as is currently the case. As the price of gold rises and entices more investors into paper gold the XAU/Gold ratio should rise with it.
I can see why you were confused. He first did the XAU/Gold graph and then the Gold/XAU graph, and referred to one incorrectly.
My favorite measure of investor psychology is the XAU over gold. At tops, investors favor the shares so the XAU is high and at bottoms they favor the metal so gold is high relative to the XAU. We just hit the highest ratio in history.
The highest ratio in history is the Gold/XAU ratio, not XAU/Gold as was stated (which is at its lowest). So in relative terms physical gold is more desirable than paper than it ever has been, thus lending creedence to a bottom. The logic is sound, just a misnomer.