Yes, keeping pet monkeys can be considered cruel for several reasons. Monkeys are highly intelligent and social animals that require complex environments and social interactions to thrive. In captivity, they may suffer from stress, boredom, and loneliness, leading to various behavioral and health issues. Additionally, the exotic pet trade often involves cruel and unsustainable practices that harm wild populations. It is generally recommended to support conservation efforts and admire monkeys in their natural habitats rather than keeping them as pets.