The reality is that postural yoga, as we know it in the 21st century, is neither eternal nor synonymous with the Vedas or Yoga Sutras. On the contrary, modern yoga was born in the late 19th/early 20th centuries. It is a child of the Hindu Renaissance and Indian nationalism, in which Western ideas about science, evolution, eugenics, health and physical fitness played as crucial a role as the ‘mother tradition’. In the massive, multi-level hybridisation that took place during this period, the spiritual aspects of yoga and tantra were rationalised, largely along the theosophical ideas of ‘spiritual science,’ introduced to India by the US-origin, India-based Theosophical Society, and internalised by Swami Vivekananda, who led the yoga renaissance.
In turn, the physical aspects of yoga were hybridised with drills, gymnastics and body-building techniques borrowed from Sweden, Denmark, England, the United States and other Western countries. These innovations were creatively grafted on the Yoga Sutras—which has been correctly described by Agehananda Bharati, the Austria-born Hindu monk-mystic, as ‘the yoga canon for people who have accepted Brahmin theology’—to create an impression of 5,000 years worth of continuity where none really exists. The HAF’s current insistence is thus part of a false advertising
campaign about yoga’s ancient Brahminical lineage.
Nanda is surely correct that yoga as it is currently practiced owes much to innovations in the later 19th and early 20th centuries, including influences from the West. But the article's framing seems a little misleading. The reality is, despite the modern innovations, there is continuity in the yoga tradition, as Nanda herself demonstrates in discussing the history of the yoga asanas or postures:
The four Vedas have no mention of yoga. The Upanishads and The Bhagvad Gita do, but primarily as a spiritual technique to purify the atman. The Bible of yoga, Patanjali’s Yoga Sutras, devotes barely three short sutras (out of 195) to physical postures, and that too only to suggest comfortable ways of sitting still for prolonged meditation. Asanas were only the means to the real goal—to still the mind to achieve the state of pure consciousness—in Patanjali’s yoga.
So, yogas is mentioned in the Upanaishads, the oldest of which were probably written in the 6th century BC, and some of the asanas were practiced at least as far back as Patanjali's Yoga Sutras, which depending upon who you ask date back to somewhere between 100 BC and 500 AD. That's at least 1,500 years of history to the asanas before the Theosophists and the Swedish gymnasts got their grubby paws onto hatha yoga. It's no doubt true that yoga as it's practiced today differs a lot from yoga as it was practiced in Patanjali's time, but that's not a very damning or suprising claim. Again, the problematic aspects of Nanda's piece stem mainly from the one-sided character of its framing or tone. One could, for example, imagine a person who completely accepts Nanda's factual account of the history of yoga writing an article with the breathless headline, "Roots of Yoga Extend Back 2,000 Years!"
Nanda herself admits that there are historical roots to modern yoga in India, but she claims that the people practicing yoga were little more than drug-addled misfits and magicians:
There are, of course, asana-centred hatha yoga texts in the Indic tradition. But they definitely do not date back 5,000 years: none of them makes an appearance till the 10th to 12th centuries. Hatha yoga was a creation of the kanphata (split-eared) Nath Siddha, who were no Sanskrit-speaking sages meditating in the Himalayas. They were (and still are) precisely those matted-hair, ash-smeared sadhus that the HAF wants to banish from the Western imagination. Indeed, if any Hindu tradition can at all claim a patent on postural yoga, it is these caste-defying, ganja-smoking, sexually permissive, Shiva- and Shakti-worshipping sorcerers, alchemists and tantriks, who were cowherds, potters and suchlike. They undertook great physical austerities not because they sought to achieve pure consciousness, unencumbered by the body and other gross matter, but because they wanted magical powers (siddhis) to become immortal and to control the rest of the natural world.
There's probably something to this characterization of the history of yoga in India, but Nanda postulates a pretty heavy dichotomy between the "ganja-smoking" yogis on the one hand and the "Sanskrit-speaking sages meditating in the Himalayas" on the other. Sorcery overlaps traditional Indian religion just as it did ancient Greek or Roman religion, or just as Voodoo in Haiti overlapped with Catholic Christianity. On the other hand, Nanda's piece does serve as a useful corrective to the many historical errors asserted by practitioners of yoga, such as the evidently common claim that yoga is discussed in the Vedas or that yoga has a 5,000 year history (among many others). Her point of view is worth taking seriously, even if the framing is misleading.