One Finger in Particular...

When Bart found himself in the dungeon reserved for non-piano players, there was a sign that said, "DUNGEON for Scratchy Violins, Screechy Piccolos, Nauseating Trumpets, etc, etc." Directly above the sign is a hand pointing with its *middle finger* towards the main dungeon area.

Is this a clever joke, or is it simply an amusing accident? Either way, it gave me a chuckle.