Humans are certainly different to dolphins, but I sure hope that some alien race doesn't land on Earth some day and say "It's ok to kill and enslave humans indi

Humans are certainly different to dolphins, but I sure hope that some alien race doesn't land on Earth some day and say "It's ok to kill and enslave humans indiscriminately because even though they are sentient and intelligent, they are very different from us Xlarblargians." This is very simply an extension of the Golden Rule to other sentient species beyond humans, starting with the ones that we know about and are closest to us. And as Colin points out, the "equating X to humans does no one any favours" line has been used before in history.