Yoga includes a full set of philosophy, guidelines to daily life, and a lot more, in addition to the physical movement.
IMHO yoga is "anti-social". It's purely for the own good of the yogis. Traditionally yogis didn't care about anything outside their body. They didn't care what was happening in the society, or how other people lived their life. For this part, yoga is kinda selfish.
The idea of "no attachment" means everything other than the body and mind should be detached, even family, even clothing.
Therefore, yoga is basically not something to "show off". Since true yogis don't try to inspire or influence other people.
A lot of advanced practice require extremely high concentration of mind. Any distraction could fail the practice and could cause big harm. Any intention other than the practice itself, e.g. to shoot a video for others, is regarded as a distraction.