Rich people may make up a negligible percentage of the world's population, but they do influence things far more than most. Much of the poverty in the world is because the wealthy have repeatedly used their wealth to crush attempts to spread democracy, equality, basic human rights, unionization, etc. As a kid, I remember watching the reports about Tienanmen Square. It was a bad event, and the news made sure to let me know it in case I wasn't bright enough to figure it out myself, because commie China (as opposed to the good pro-capitalism China we have today) did it. In that same period, US businessmen and politicians were still financially supporting any anti-communist psychopath that came along in Latin America, Africa, and the Middle East--psychos like Bin Ladin, and the Contras.
Another, much worse thing they do however it try to help. Seriously. For example we all can agree that AIDS in Africa is a bad thing. The Bill and Melinda Gates Foundation agrees, and so it uses it's funds to help in the good fight.
You may be wondering how that's a problem. Well, it seems the foundation offers financial incentives to hospitals and health care professionals to focus just on AIDS. As a result more people die from malaria, and other treatable/preventable diseases than should.
It doesn't stop there though. Things like providing clean drinking water, adequate transportation, and fighting malnutrition also get pushed to the back burner. You could have a hospital in a city providing magic cures to all diseases, but it won't do people in remote villages any good, since they can't get to it.
You can give people all the latest greatest AIDS treatment drugs you want, but if they are extremely malnourished their bodies can't use it effectively, assuming they can keep it down at all.
If you give people dirty water to wash their pills down with, theres a good chance they'll get sick and die, especially since they already have weak immune systems.