Yes genetically they are the same but any one who deals with working sport dogs knows that pedigree makes a lot of difference in dogs. Are there some GSP's that still retain the natural ability and drive that they were breed for, I am sure of it. However the odds of getting a dog from the average AKC litter that will perform as well as a dog from an average DD litter is much less. It is a simple matter of breeding standards and controls. It is very well proven that breeding practices and pedigree make a huge difference in the quality of animal produced.
I had a little 45lb runt of the litter liver and white male that lived to the ripe old age of 15 and would have disproved you every single day of his life. He had a few champs in his bloodline and some good solid AKC hunting stock as well. He lived for the hunt, could tell the difference betweena rifle and a shotgun and the over under from the autoloader. He'd hunt birds, retrieve doves, track deer, find lost cats, protect his house, and everything else you could want. Many of his offspring have been doing the same for years now. The country of origin has little to nothing to do with a dogs abilities, like people those are individual traits. Sorry fellow, I'm not buying the Nazi Canine rap.