Why do Texas prisons ban 'Freakonomics' but not Adolf Hitler's 'Mein Kampf'?

More than 10,000 books are banned from Texas prisons, but they might not be the ones you think. Alice Walker's The Color Purple, which won the Pulitzer Prize and National Book Award for fiction, is not allowed. Neither is Freakonomics, the 2005 bestseller that explained concepts such as cheating at school and parenting techniques using economic theory.
Read more: https://www.dallasnews.com/news/crime/2017/11/27/texas-prisons-ban-freakonomics-big-book-angels-adolf-hitlers-mein-kampf?source=Snapzu