Genos Historia kind of takes credit for this theory. It's really Davidski's theory, and he's been posting the evidence for it on his blog Eurogenes for a long time; a blog in which I know that Genos Historia reads and comments on. Forgive the kind of hoaky and long-winded delivery. I actually think Genos Historia is doing some good work with his own PCA analysis, but for the most part, he's just repeating theories from more academically serious men.
He's also making slightly too strong of a statement. While at an autosomal (i.e. whole genome) level Yamnaya and Corded Ware are very similar, they are not completely the same, and they are also not just differentiated by some excess EEF admixture. Corded Ware also have some excess WHG admixture, which admittedly might have come via EEF peoples such as the Vinca or Cucuteni-Tripilia cultures. Many of the later Corded Ware populations also absorbed SHG population groups as they entered Northern Europe, especially the Fennoscandia area, and daughter cultures of the Corded Ware, like the Nordic Bronze Age, show significant levels of admixture from this group.
In any case the proto-Corded Ware peoples had a slightly different economic system, and lived in a different ecological zone, and did so from the beginning. Yamnaya became, over time, so obligatorily steppe-based and transhumance focused that they could not and did not have any sedentary domesticated animals with them, especially pigs.
