To my knowledge, Taurine is an Amino Acid that your body already produces on its own. With energy drinks, they give your body the extra Taurine which acts as a major stimulant, arguably moreso than Caffeine. As you know, Amino Acids are very good for you and Taurine is no exception.
I believe Taurine is also found in many pet foods, too...especially cat food. I was looking on a medical website about Taurine and it is said to be very good for eyesite.
From a legal point-of-view, beverages and pharmaceuticals are very different industries.
Some are required by law to report certain things about substances and the amounts of them while others are not.
That's why with any medicine or caffeine pills, they're required by law to state how much caffeine is contained in the product, but soda and energy drinks are not; they simple state "caffeine", and the only amount indicator that we have is how far down the list the word appears, since beverages are required to state ingredients in order of the greatest amount to the smallest.