Humans are such strange things.
I grew up on Science Fiction and Fantasy, so I kinda of have the knowledge backed in my head. One doesn't have to be a human to be considered a person. In my opinion Data is a person. It almost has to do with something greater, like a soul, or heart so to speak. A person is someone who has feelings emotion some depth, more than flesh and bone, but the ability to have a greater meaning, almost like philosophy in a way.