Because your neighbor is the same species and so you have some idea of what it's like inside their head. When your neighbor is a different species, this is pre

Because your neighbor is the same species and so you have some idea of what it's like inside their head. When your neighbor is a different species, this is pretty much exactly what humans do: kill it. The more unfamiliar, the faster it gets killed. Is it bad for the ecosystems, biodiversity, your soul? Yes on all counts. But it's pretty consistent human behavior.