This was shortly after the tremendous damage done to the faithful by the Albigensian Heresy through the early 13th century. The Albigensian Heresy was the result of sacred scripture ending up in the hands of people who had no authority to interpret it.
Context is your friend.
"Context is your friend."
On this topic it truly is my friend for there is no shortage of examples of the Catholic Church trying to keep the Bible out of the hands of the common people down through history.