There are many animals that eat spicy food, but most of them don't feel spicy.
The spicy taste of pepper fruit mainly comes from capsaicin. For this plant, capsaicin is an act of self-protection.
Some animals have receptors that can bind capsaicin on their taste organs (such as rabbits), and capsaicin can make them feel pain and stay away from peppers. Many animals (such as some birds) do not contain this receptor, so they will also eat the fruit of pepper.
The former (animals that can feel spicy) can often digest pepper seeds, while the latter can't. Therefore, capsaicin can be regarded as a way for pepper to protect itself. Only animals that can't digest pepper seeds can spread seeds for themselves.
People who can feel the spicy taste of capsaicin but are interested in eating Chili peppers may only be human beings.