How to act

Isn't it funny how so many people don't know how to act?  You would think that when one stepped into a library - a place designed for study and quiet contemplation - one would attempt to keep their noise production to a minimum. But no - most people don't.  Sorry to rant even more than my usual standard, but what on earth is wrong with this world???  (Aside from the fact that the billions of dollars invested in yachts, moving yachts by ship, and the design of even more expensive yachts could feed the billions of people who don't even have access to clean drinking water ...) 
One example: while walking through the library today I discerned the generic melodies (?) of a popular R&B track.  You know the kind - where every crescendo of vocal melody sounds like the sudden strangulation of a robot on ice (I think it was Cher who started the trend - Do you belieieieve in life after love).  A disgruntled gentleman looked over at me and pointed to the other side of the divided desk.  A young lady gawked at her facebook page.  Behind Facebook, YouTube was (not so) quietly lurking.
"Excuse me, the music is a bit too loud, can you please turn it down?"
The young lady looked at me blankly, before moving the audio cursor down.
"Thank you" I replied, before walking away.
Sure, she had done what I asked, the only thing was - the music was still very audible, in fact, it seemed just as loud as it had been before my intermission.  Noticing the same gentleman's agitated expression, and hearing his sigh (just audible above the music) I returned. 
"The music is still too loud" I said.  She pointed to the sound control.  Being at its minimum she said "Its as low as it can go - if I turn it down more I can't hear it."
"This is a library" I returned "We have to try to keep the noise down because there are people trying to concentrate.  Sorry."  With that I walked away. 
Why did I need to explain this?  Perhaps she had never been educated on the primary role of the library in our society.  I guess I shouldn't judge.  We do provide computers with sound after all, and we don't restrict access to facebook or YouTube.... My thoughts were interrupted again with the twitching ring of a mobile phone.
"Yeah?  At the library.  THE LIBRARY.  (Snickers)"  That same girl was now talking without restraint on her phone.  "Cause you're such as CUTIE" She crowed in a Kath and Kim dialect.  So much for my explanations.  Oh well.  I guess some people just don't learn.