In yoga, we concentrate on pose, breathing, concentration, and meditation. But those are only 4 of the 8 limbs of yoga as articulated by Pantanjali in the Yoga Sutras. The first of the 8 limbs is yama or restraint. One of the five yamas is nonviolence or more famously ahimsa—doing no harm to any living creature in any way, shape, or form. To be a yogi, according to this criterion, you have to be a good person. The good person is the restrained person, who under no circumstances causes harm, steals, lies, or is greedy and practices abstinence. Unfortunately, the moral core of yoga has been forgotten or more accurately: was never learned in the first place.
Yoga teaches the great virtue of restraint. Without restraint, we tend to become violent in both action and thought. We can’t ascend to yoga heaven (Samadhi) without mastering restraint on every part of bodies and minds. Yoga is indeed flexible enough to flourish in consumerist cultures that use it for weight control and competition. But anything, if twisted enough, breaks and that includes yoga. Perhaps even now yoga is broken.