Spectacular evil is much easier to achieve than spectacular good. If that scumbag in Colorado had put the same amount of cleverness and effort into planning a party for developmentally disabled children, we'd never have heard of it.
I'm not suggesting we need to be spoon-fed feel-good pabulum on the front page to drown out the evil. I'm saying: impressive good is just harder to do than evil - because people are fundamentally good. Because right now, people everywhere are engaged in actively planning and executing good for each other, from simple to elaborate, from one-time to long-term. Speaking relatively, there are only a comparatively few sick fucks trying to and planning to get our attention with death.
Of course they succeed. They succeed because evil is fucking easy, not because they're any good at it.