It depends on the circumstances and how the pet is cared for while in the cage. Keeping a pet in a cage can be considered cruel if the cage is too small, dirty, or if the pet is left in there for extended periods without proper exercise or social interaction. However, cages can also provide a safe and secure environment for pets, especially when used for transportation, training, or as a sleeping area. It's important for pet owners to ensure that their pets have enough space, enrichment, and social interaction to prevent any cruelty.