Note that the article is not arguing that yoga isn't ancient at all, but that yoga in the form "exported" to the west refers to a practice that is a distinct form of physical exercise that really is separate from traditional yoga, and that the new form borrows a lot from Scandinavian gymnastics.

It's not saying there aren't physical aspects to traditional yoga either, just that the physical practices of traditional yoga didn't fit the needs of the people who pushed the "new" poses.