This photo above is the only part of the giant ape that the scientific community calls Gigantopithecus that has been found, except scattered teeth. It looks rather human, don’t you think? Maybe they just don’t recognize that they have the jawbone of a real giant? The photo is from the History Channel.
This is a gorilla jawbone. Note the large canines not found in the Giganto jaw. I understand they have never been able to get DNA from a Giganto bone or tooth. But if they got human DNA from it, they would just think it was contamination, and not report it. So that would be consistent with at least some of these bones and teeth being from giant humans.