Nowhere. Due to his actions you could say he doesn't care about humans, but hating them is a bit silly in my opinion.Where was it ever stated the he hates humans?
Remember that Vergil is not Sparda, he may want to emulate him in power and to some extent personality wise, but it does not mean that he is obliged to share his ideals on numurous things like protecting mankind for justice. He is his own character with his own goal(s).That's up to debate. I still believe he would have only allowed the people in the city to die. I'm sure he knew of the loop hole... Killing most of the people on earth just makes no sense. It goes completely against Sparda.