Doh, this is so wrong, and I note in your criticism of Howard Buffet that you simply don't understand why.
Simply, the global system of capitalism is unfair.
The winners take order-of-magnitude multiples of reward, completely disproportionate to their efforts, compared to the poor. It's a power law, and part of that is the self-reinforcing effect that having wealth makes it easier to get more wealth. The only way this can happen is that wealth is shifted from the poor to the rich, and of course Wall Street is the very pinnacle of this system.
Like in sports. The best players are multi-millionaires, the worst get nothing at all, indeed they end up contributing towards the winners by buying sponsored sports equipment, paying for training, seminars, etc, attending sporting events, and often volunteering for free.
That might be fine for sports. But it's not what we want in life.
By proposing that do-gooders work on wall street, you're advocating people do exactly what Howard Buffet talks about. Taking with their left hands, before giving with their right.
The Aid industry is just a salve on the problem, and though it obviously helps individuals and saves lives, it doesn't address the underlying problem. Indeed it can make the most glaring of the symptoms disappear to a point that to some people the problem doesn't appear to need a solution.