The founding father were engaging perpetuating the existing dehumanizing system of slavery, not answering any new questions about new things.

The thing about new possibly "person" entities that arise - the case of machine intelligence you have two questions - would it qualify as a person and should you actually build it. It seems like if you get close to humans, sure a built thing might qualify as a person. Should you build it? I'd the answer should be a hard no. Not 'till you a sign-off from say, the whole human race, which I think you could get.

Now the present entities seem very far from persons in any case.