I touched on this a bit back in Quint's Quest #117 that, Asimov's three laws exist to protect the human race from any robot getting too big for their britches, as it were. You'll note that I said "Human race". This means that robots are free to butcher sentient alien life to their heart's content, which technically makes an army of robots perfect for a human conquest of the galaxy... Wait a moment, wasn't this part of Warhammer 40,000's backstory?