Because it seems illogical, at least to me, to believe that inert objects could be conscious. Brains are as far from inert as can be. Computers are basically magical silicon runes imbued with software, also as far from inert as can be.

Proposed categorization: "definitely not conscious", "maybe conscious" and "definitely conscious". All living things belong in "maybe conscious". Each person is sure that they belong to the "definitely conscious" set, but people cannot prove this to each other. Their empathy causes them to add other people to the "definitely conscious" set. Many choose to add animals to that set too. Some add even inanimate objects to it.