It doesn't only happen in the United States.
From the Guardian:
Muchamore, who lives in nearby Crouch End, was lined up to speak at Highgate junior school in mid-November, but was informed this month that his appearance had been cancelled and his books removed from the junior school's library following complaints from parents. "Highgate School invited me to do an event, then decided [to] read my books first and promptly banned them. Tossers..." the bestselling author wrote on Twitter.
I know this sounds crazy, but maybe next time, they'll think about reading the books BEFORE extending the invite.
Also, is the library supposed to serve all of the students in the school, or only the youngest ones? Pulling books that are geared towards the older end of the spectrum suggests the latter, which seems rather unfair to the tweens.