Why can't cats be persons? They certainly have personalities. And they can recognise themselves in mirrors; at least, my cat reacts differently to seeing himself than he would do to another cat.
Why not? We've tried to abuse test like IQ and apply them to dolphins and apes and such. Dogs and cats also seem to have a measurable IQ and they certainly have personalities and emotions. And outside of a few notable areas, eating any of these animals is generally considered taboo.
They are also a lot cuter than dolphins.