The theme best supported by the verbal irony in this passage is "Corrupt leaders use propaganda to remain in power."
In the scene, the pigs justify their decision to sleep in beds by manipulating the definition and the context of the rules they established, highlighting how they twist language and logic to maintain control over the other animals. The pigs' rhetoric attempts to mask their hypocrisy and reinforce their authority, demonstrating how those in power can distort truth and use propaganda to justify their actions and maintain dominance.