>>It should be obvious to anyone, that when you have more wealth than 99.5% of the world, you owe the rest of the world.
Unless you are a king, dictator or some force of evil. Building 99.5% of the wealth in the world will mandate you to build empires of business, solve problems, provide employment to millions of people around the globe.
So they should give back to chance? How does one do that? It may be a nice turn of phrase, but sound like completely meaningless if one takes a minute to think about it.
One should be charitable because it's human to be compassionate to your fellow human being, not because being successful automatically puts you in debt to the God of Chance, which debt should be repaid or else. And not because by being successful you stole your success from somebody else.