As I see it Billionares seem to be generous offering of their money to rebuild, they could have not offered anything at all. Everyone has the tendency to greed not just the rich. Really need to break the dangerous movement to vilify people who have money. Besides you don't have any idea what other things(charity) they do. So you are judging them.
Everyone's greed is a contributor to the worlds trouble. I see multiple reasons for the route of the worlds ills. Power grabbing, Killing, Stealing peoples property, breakdown of the family unit. And on and on.
When the brush is broad the strokes attack the innocent? Which was probably not the intent. Even the poor can be greedy? And, the rich can be generous?
“The object of life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane.”
― Marcus Aurelius, Meditations