I wonder what the concern is. Are people so desperate for validation or so threatened by alternative practices that we need to continuously ruminate on this question?
One of the things that I have learned from my practice is to be concerned with what's going on on my mat. That is the only thing that I have any control over, a small rubber rectangle of space, for about an hour and a half a day. What people are doing on their rectangles is their concern. The reason they got on their rubber rectangles is their concern.
And yes, this is coming from an Ashtangi. If you know the Ashtanga practice, you know that it is said to be a "classical" form of yoga. Does that make it superior to other practices? It does for me. But maybe not for you, and that's ok.
There are many paths to the same destination. As for the practitioner who isn't interested or looking ahead to the destination, who is maybe just showing up for the workout, aren't they practicing what we've been preaching? That it's not the destination that matters but the journey.
So let them work through their samskaras (even if they aren't aware that that's what they're doing) to blaring hip hop music while wearing $200 yoga outfits all in the name of a good workout.
There is enough interest in the "classical" forms of yoga, as evidenced by the constant media scrutiny of the subject, that these off-shoot imaginative styles are hardly a threat.
If it seems like I let this topic ruffle my feathers, it's true, I do. Thanks to the wonderful studios where I've practiced (Back Bay Yoga, The Massage Center, and Shanti Yoga Shala), I've been exposed to all kinds of yoga. And while I've chosen to practice Ashtanga almost exclusively, I have come in to contact with some of the most spiritually aware - if not enlightened - individuals who enjoy all forms of yoga. It's often those people who are filling the studios in the evenings that support (yes financially, but also emotionally) the space for the morning "classical" practioner. And then on occasion, the practitioner of the trendier forms of yoga, gets curious about what is going on at 6am in these studios. They set their alarm, come to the studio, and practice the "classical" form, and then, they decide for themselves.
Excuse the rambling. This is long hand for "Can't we all just get along?"