Hmm, I found this quote in a couple places with "raison" in it. I can't say for sure if this is some accepted form of "raison d'etre" or not, but why would the author not just say purpose, or reason for being if he meant that. And really I don't think that is really accurate anyway. I might say For television's main goal is reflecting (or showing)... or For television works best when it is reflecting.... Either one would be more accurate.