I would actually argue that yoga is now sufficiently commercialized as to bear little resemblance to anything "ancient" or "mystical". I can buy a book, get some videos or take a class and hear nothing spiritual at all. (Side note: Mark Lauren, in his fairly good _You Are Your Own Gym_ covers yoga a bit). This isn't to say there's not lots of people selling the "spiritual enlightenment" line.

I think all exercise programs tend to have a something to sell, because otherwise how do you make money? It's an interesting balancing act, however. Your doctor can tell you "get more exercise", but that's a pretty abstract concept that requires planning, commitment and is by definition kind of uncomfortable. So a whole industry has grown up around branding exercise. It works, too. Some of it is better than others, but people, myself included, buy it. We might buy it because we're gullible, we might buy it because it's easier than coming up with our own plan or more interesting when executing it.

But the number of books that grace the shelves with words like "warrior", "ultimate", "prescription", "philosophy", "enlightenment", "Spartan", "SEAL", etc, etc, etc. is pretty staggering. But frankly, whatever works. Insurance companies often incentivize gym memberships, but rarely do they pay for you to regularly see a trainer, so whatever is safe that gets people exercising. I complain, but it's not even in the same league of problematic as unregulated administration of pharmaceuticals by spiritual leaders.

In practice, Yoga is pretty woo free for the most part. I was also concerned to try it because of the woo but my friends all said I'd like it.

I took some classes and not a single instructor treated the class as anything but an exercise class with some meditation at the end. I even took an "alternative" yoga class with weights.