It's seriously a mental illness, a "rich mind virus" if you will, and we should design the rules of society accordingly.
Some of these people have an innate drive and even some skills that could contribute to society in a positive way. There should be a place for them just like any other disabled person. But that doesn't mean they should be able to run wild until they harm others.
We as a society need to get away from the tendency to categorize a person as good or bad based on one aspect of their life and generalizing that to everything else. Assuming that somebody is moral, ethical, honest, or a capable leader based on their net worth is definitely one of the more egregious examples right now.