Who is responsible for the banning of the books?

Mankind was responsible for banning the books.  When
Beatty comes to speak to Montag he tells him that "Once books appealed to a few people
here, there, everywhere. They could afford to be different.  The world was roomy" (pg
54).  But then the world became crowded and in the twentieth century "books cut shorter.
Condensations. Tabloids. Everything boils down to the gag.  The snap ending." (pg 54) 
There was no need to know anything after a while except pressing buttons and having a
good time.  Beatty explains that the word "intellectual became the swear word it
deserved to be " (pg 58).  Then when Montag goes to meet Faber, Faber is embarrassed
because he didn't do anything to stop the decline of written material.  He says "I
remember the newspapers dying like huge moths.  No one wanted them back.  No one missed
them. " (pg 89).  The government actually created the job of burning the books,
keeping people's peace of mind, because as Beatty says, "Who knows who might be the
target of a well read man" (pg 58)