They (Mothers of Liberty) want to ban a number of children's books. Particularly those that show the Catholic church is a bad light, such as the imprisonment of Galileo for saying the earth revolved around the sun, or talking about the Inquisition or the Crusades.
They also take issue with a picture book about the mating of seahorses, showing positions and discussing how the male carries the eggs.
In part they simply just want to obstruct the truth(s), which they fidn to be embarrassing.
They want education to be at the level it was in the 18th century in other words.