Spoken like a true speciesist.

You think I'm being prejudiced against certain races of humans because you cannot imagine other animals being given equal moral consideration to humans. YOU see other animals as 'lesser beings' and so you assume that's how I see them, too. By implication, you then think I'm implying that black humans are 'lesser beings' when I compare the treatment of human slaves to the treatment of nonhuman slaves.

You have missed my point entirely.

The prejudice is all yours, my friend. My argument raises other animals up to our sphere of moral consideration - it does not diminish human rights.