A computer is a stupid machine because it

can only do what humans program it to do. It does not have the ability to think or reason on its own. It relies solely on the instructions given to it by a human operator.

A computer is a device that performs tasks based on instructions given to it by humans. It is not inherently "stupid" because it is designed to accurately execute tasks and process information quickly. However, computers lack the ability to think or reason like humans, which is why they are often considered "stupid" in comparison. Nonetheless, computers are incredibly powerful tools that can process vast amounts of data and perform complex calculations, making them invaluable in many aspects of modern society.