To me: What makes sentient nonhumans so special is that they are Not like humans. And that they don't think like us. They do just fine on their own without our inventions (especialy the ones that might pound us back to the stone-age).

Why must any other being be like "us" in order to have basic "rights"? The right not to be the property of humans to do as we damn-well-please to them!

Being sentient should be enough to accord them; to grant them, "their" own lives.

Ah, humans....