Villains, especially cartoon villains, are remarkably narcissistic and prone to childish vandalism. Whenever there's a landmark with a famous face on it, there's a good chance the villain will demonstrate his need for attention by putting their own face on it instead (or some ridiculous caricature of a real face, to emphasize their whimsicality). Mount Rushmore (which features U.S. Presidents Washington, Jefferson, Teddy Roosevelt and Lincoln, in case you've forgotten) is an especially frequent target of this; the Statue of Liberty and the Great Sphinx of Giza are other popular venues for refacement.