There are many possible reasons why cats like to watch their owners poop. Here are some possible explanations:
Curious by nature: Cats are naturally curious and always eager to explore new things. For cats, the act of humans entering the toilet—a special space for excretion—can be a very novel and interesting thing, thus arousing their curiosity and making them want to investigate.
Social Needs: Cats are social animals and enjoy interacting and communicating with their owners. When their owner enters the bathroom, the cat may see it as an opportunity to socialize, and will therefore follow the owner into the bathroom to observe their behavior and maintain interaction.
Territoriality: Territoriality is very important for cats. Cats may perceive their owner's elimination behavior as marking territory or asserting their presence, and therefore will show great interest and observe it closely.
Need for security: Some cats may observe their owner's behavior due to a lack of security. For these cats, observing their owner's behavior in the litter box may be a way to gain a sense of security, as it allows them to maintain close contact and observation with their owner during this process.
