It isn't that the world is full of terrible people, it's that there are to many people along with the bad people. Yes he talks about fools who don't give back consuming the future, but that's not his main point. His main point is that there are far to many people, and they're only growing in number and the future is in danger as a result. And remember-
"Kalos is beautiful right now!
There will be no foolish actions if the number of people and Pokémon do not increase. That being said, the future isn't decided. You can't be sure each day will be like the one before."
"This world will eventually
reach the point of no return... Saving the lives of all is impossible."
"The strength to protect, huh? But what are you really protecting? A tomorrow that will only end up being worse than today?"
He's aware of the world as it stands now, full of decent people. But he fears for the future.
Something else, everyone talks about him trying to help everyone with his lab and failing as the straw that broke the camel's back, but I think it might've been something else. He's the descendant of someone who partook in the ancient war that was started for unknown reasons, wouldn't be surprised if it was over something selfish. EDIT:
Scratch that it was the younger brother (who was Lysandre's ancestor) who started it for greedy reasons. Then you look at something you hear in his final stand-
"If that were possible, all wars would have ended long ago!"
Interestingly enough, all he talks about before you see him in his HQ is just theft and strife. He never specifically mentions war until you and Serena/Callem face him. I think his family's history could be a big motive in his cause.
Also that last quote makes it apparent wars happen in the modern day in the world of Pokemon, we just never see them. Which is kinda unfortunate but I can see why.