Earthlings, full of diversity, generally weren't hostile toward each other. The Earth was like a big insect jar. Insects put into a jar together tended not to fight unless the jar was agitated enough. If the jar owners put different types of ants in the same jar without agitating their habitat enough, they might just work together to overthrow the jar owners and build a happy society where everyone was equal and free. And we can't have that. Gotta keep shakin' that jar.