Why does the professor quote an eyewitness’s account of the performance in Paris?

Listen to part of a lecture in a music history class.
Professor: Today I’d like to look at an important piece of music of the 20th century. It’s a ballet, so you might imagine graceful melodies and dancers, refined and beautiful, but this traditional view of ballet was challenged and altered one evening in Paris in May of 1913. The theater was reopening after extensive renovation and the audience was impressed when they saw the newly restored elegance. The first piece that evening was a very traditional ballet with unremarkable music. lt was the ballet that followed which shocked the ballet scene to its core. I am talking about the premier performance of The Rite of Spring by Igor Stravinsky.
    The Rite of Spring opened with some very high notes played by the bassoon, normally a deep-toned instrument. Such strained, pinched notes that many in the audience had no idea what instrument was playing. Soon after another instrument came in playing a different melody with a slightly different rhythm. These two melodies really didn’t match each other. Gradually, more and more instruments started to be played. To the audience’s surprise, each instrument was perfectly delivering a beautiful melody, but none of them really made sense with what the other instruments were playing. It sounded chaotic and things got even more crazy when the curtain was raised. The audience were shocked to see the dancers wearing rough costumes and not poised elegantly like traditional ballet dancers. I should mention here that the choreography was created by Stravinsky’s collaborator, Naginski, and Naginski, in the words of an eye witness, Naginski had the dancers repeat the same gestures and feet stamping hundreds of times.
    It wasn’t too long before the audience started to get rowdy. The audience was divided between those who enjoyed the chaotic performance and those who were downright angry at what they had paid to witness. They began to shout at each and soon people were actually fighting in the aisles. The lights were even turned on so the police could escort some of the offenders out of the building, though that didn’t really seem to help much. In fact, it’s amazing that the performers actually made it through the piece, but when it was over, while applause broke out from some who were ecstatic about what had happened, and angry shouting from many others who were shocked and appalled by what they felt to be a complete betrayal, a breakdown of traditional ballet. The chaos that evening was a great disappointment to Stravinsky. Ironically though, the producer of the program that night was not at all upset. He was overjoyed that everyone in Paris would soon be talking of nothing but this, well, what many were calling, this terrible scandal. Then as now apparently, producers like almost any kind of publicity. Even notoriety sells seats, they say.
    So, that’s what happened at that first performance of The Rite of Spring. What’s not quite so clear is why, what set off this huge uproar? Was it that Stravinsky’s music was such a break from the past? The retelling of the events of that evening certainly created the popular impression that this piece marked the dawn of a new, modern age in orchestral music. That helped establish the piece’s reputation as an important, even revolutionary, milestone in musical history, and I’d say this reputation is pretty well deserved, but that’s actually a different question from the one we were trying to answer. As to what in fact caused the near riot, well, consider this: after the first few minutes of the performance, there was so much shouting in the audience that Stravinsky’s music could hardly be heard. I’m hardly alone in concluding that it was less the music than the staging that outraged so much of the audience. Ballet lovers were so shocked by Naginski’s choreography in many cases, that the music, well, let’s just say it didn’t get a fair hearing. It was only when the work was performed in concert without any dancers about a year later that Stravinsky finally felt it a true success, but that was just on the eve of World War I and so it wasn’t performed as a ballet again for seven years. After the war, when The Rite of Spring finally returned to the stage as a ballet, Naginski’s choreography was abandoned and with dancers performing totally new steps, the work went on to become a modern classic.