I think of evil as a problem primarily of ignorance--I think I got that from Socrates. Ignorance can be divided into two main types, which I'll call accidental and internal. Accidental ignorance is when someone just doesn't realize that the thing they did was harmful, but you could tell them and they'd understand. Like, if I were kicking rocks off a cliff and one of them accidentally hit you and you said "OW" and I said "OH! Sorry!"

Unfortunately, as you point out, in a complex modern society like ours, the consequences of our actions are often so remote and removed that it's difficult to perceive them. Like, sure, lots of Iraqi children and coastal wildlife have died as a result of our dependence on oil, but most folks don't think "Oh gosh, I'm murdering a child," every time they get gas. They think, "Gotta get to the grocery store, drop Bobby off at ballet class, pick up a new hammer..."

Internal ignorance is when someone just lacks the empathy to understand that they did something harmful. "What do you mean that was racist? That wasn't racist. You're just trying to make me look bad!"

But on the plus side, that same complexity of society allows us to have the communication technology to talk to people on the other side of the planet and see pictures of them and understand that our actions do have effects. So I still have hope for society as a whole, that we have been and will continue, in general, to improve.