We must remember that we are all human and we are all simply responding the best way we know how, to our environment. The evils of the world are a reflection of the interaction of humanity and the environment/system in which they live/face. If more people realized that, I believe the world would be a much better place.
It is important to note that the greedy, hoarders are also a product of their environment and aren't evil; they are just doing what they know how to do due to the environment they grew up in etc. A lot of their problem lies in their insecurities and lack of appropriate social interaction. Being wealthy brings its own demons. I don't think enough time is spent talking about that aspect of things either. For example, simply being wealthy can make many people feel lonely. To fill that hole, many try very hard to fill it with more money.
The problem is that in our EEA (environment of evolutionary adaptedness), such severe wealth differentials were not possible. Therefore, in a relatively short period of time (i.e. from when people first started using money and hoarding it), huge differentials in power (i.e. money differentials) have been able to occur with little time for humanity to evolve in response. In other words, we used to live in small tribes, were there was a certain degree of order, but that was also somewhat flexible or different members had different strengths. However, it is likely that not many people had the kinds of power over others that we see today. In addition, even those who were higher in the social hierarchy were still not ostracized from the group. Do to the flexibility and changeability of the power in these social hierarchies, people remained close, socially. This is not what we see today. Thus, the wealthy try to fill their social holes with money, snuffing those out beneath them. The only way to fix this problem is to bring the classes closer together; to get everyone interacting again. One of the ways to do this is to decrease the income differences we observe.