This is crazy.  It reminds me of how the FBI took photos of people protesting the Viet Nam War.  Are we expected to live in fear?  Mao's book has no relevance on the world today, everyone knows it, and yet some agency finds it worthwhile to question someone who checks out a copy of Mao's book, as if to say, we are watching you, and we want you and your friends to know it.  It's really amazing and sad.