That you can help more people if you have more money is simply a fact, it's not an argument based on the statistically average behavior of wealthy Americans. And as to the sources of wealth, the economy is not a zero sum game. Lebron getting paid $30mm doesn't take money away from anybody.

As far as Warren Buffet goes, I don't worship him - he got pretty lucky, was a little bit disciplined, and rode a wave of increasing value of American stocks for 40 years - but to say he has been a "premier monopolist" (hint: having high profit margins on the back of brand recognition like Coca-Cola and Apple have done is not what a monopoly is) or is a "parasite on economic growth," is only your own preconceived bias.

And as far as the behavior of the very wealthy in general, the things you describe are things that the middle class or the poor do as well. The vast majority of human beings are assholes, unfortunately. If you do happen to be a good person, though, I think the world is better off if you're wealthy than if you're poor. And if you set out to do the most good possible in the world, then choosing a career where you can make a lot of money, and then donating a large portion of it, is not a bad way to go. Doubly so if you can help people along the way, as many doctors or lawyers with pro bono hours do.