Here's why:
* Humor: The poem uses playful language and absurd situations to highlight the silliness of judging people based on superficial differences. For example, the poem states "There's no difference between a cat and a dog" even though they are obviously different.
* Satire: Silverstein uses exaggeration and irony to criticize societal biases and prejudices. He highlights the absurdity of drawing lines between people based on things like skin color, hair color, or clothing.
Overall, "No Difference" is a lighthearted but pointed poem that uses humor to deliver a message about the importance of recognizing the inherent value in all individuals, regardless of their differences.