Nice article, thanks gigantor.
And there's the lack of any Gigantopithecus fossils found in north america.
I believe it was Grover Krantz who first came up with the Gigantopithecus theory in an attempt to root his own sasquatch theories to methodological science (it should be said though that Heuvelman used Gigantopithecus as his explanation for the yeti and Krantz may likely have cribbed it for sasquatch without attribution). Unfortunately for Krantz and the field in general, he was a sloppy researcher going back to his grad school days at Berkeley. A case in point was his attempt to get sasquatch scientifically named "conditionally" even though no specimen had been found. In his paper he argued that the Gigantopithecus fossil had a horizontal rami and that meant bipedalism. One scientist reviewing the paper noted that there are living apes with very similar jaws which are not bipedal.
Krantz's book, Climatic Races and Decent Groups, where he put forth his theory used outdated methodologies and was roundly dismissed as a result. In an age of dna research and genetics Krantz was using dental anomalies, fingerprint patterns and cephalic index.
But I digress, I'm reading up on some of the early researchers so this stuff is top of mind right now.