For those who think 'Hatha Yoga' is style of doing easy postures in a relaxed way the following information might help broadening their perspective.
Hatha Yoga is not a style of doing postures but a comprehensive orientation of theory and practices that lead the practitioner beyond suffering through complete self-understanding.
Hatha Yoga started not as a 'style' but is a movement, a movement towards personal transformation and inclusive social change. The origins of Hatha Yoga are based in activism and rebellion against the prevalent Brahminical hegemony, ritualistic dogmas and perverse Tantric practices. Over past 10 centuries the main propagator of Hatha Yoga, Mahayogi GorakhNath, has inspired a long lineage of saints who have consistently rebelled against the oppressive societal order of their times and created change in their respective communities.
To break the dictates of caste system the order of Hatha Yogis were open to all seekers beyond race, religion and gender. If one takes a look at the main Gurus of the Hatha Yoga order one can see that the list comprises those from lower castes, handicaps, women and social out-castes.
The main focus of Hatha Yoga sadhana is mental regulation and release from the web of objective reality to bringing the mind back to its natural (Sahaja) state of infinite potential.
With this essence at heart, the lineages of Hatha Yogis focused more on personal transformation and social change rather than being limited only to philosophical sophistry and intellectual regurgitation.