They may be right. Dahl, best known for the movie adaptation of Charlie and the Chocolate Factory was a master at creating stupid parents and evil authority figures that children love to hate. As if anticipating today's spreading conviction that educators are more competent to raise children than are parents, he created Miss Honey, a compassionate young teacher who eventually replaces Matilda's negligent mom. Matilda's message exposes today's upside-down values.
Children learn that it's okay to punish mean parents and take revenge on tyrannical principals.
Vandalism is good when the victim is bad. Many are seduced by the message. Because I like movies about evil people. Like Matilda's crooked father, played by director Danny deVito, the monstrous Miss Trunchbull fits the bill. She stole sweet Miss Honey's house and probably even killed her father.