Terminators could kill humans so easily

Or just flood the planet with lethal gases/Nuclear radiation, etc

Yo would think a superior intelligence would know that killing Humans is really not that difficult. instead of hunting them with terminators how about using Chemical weapons or even better Biological. then you do hunt those left hiding underground.

Maybe it's not as straight forward as that when you consider that machines need power to survive, and it's hard to generate power with no natural resources, especially wind and the sun.