Of course non-practioners are horny over yoga, that’s why they are called a “layperson”! The reality is that all people do yoga, only those who are not aware of this usually don’t do it as well. If yoga is thought of as striving for union, then a sexual aspect to this is perhaps not surprising.
What boggles me about yoga clothes is how gendered the marketing is. Most makers of yoga clothes have completely separate parts of their sites for clothes intended for male and female bodies. Unlike for non-yoga clothes, it is usually quick to go through both lists because 95% or more are the women’s list, with a few frumpy afterthoughts in the men’s section. Why doesn’t anybody offer the same bottoms? Maybe just put a little pouch on the male version. I usually complain about clothes being gendered, but this seems to be worse with regards to yoga.
ETA: Also, I have been to a few nude yoga classes, and it was nice without there being anything overtly “sexy” about it. But “yoga panties” does sound funny.