I was interested in why the left hate the Koch brothers so much. I went to www.kochfamilyfoundations.org and found the following information. Understandably, it's their site and they're not exactly going to be putting themselves down, but the following facts are easy to document.

It seems to me that they've truly given back to the world. For anyone who has had a family member (or themselves) with cancer, the Koch's are doing quite a bit to help. The libs generally complain that Republicans are trying to destroy public funding for the arts. It seems to me that the Kochs are helping quite a bit.

It shows that generous donations from private benefactors decreases the government's need to tax us to death (and to control us).

Medical & Cancer Research

As a prostate cancer survivor, David Koch’s gift of $100 million in 2007 created the David H. Koch Institute for Integrative Cancer Research at MIT, which which opened March 3, 2011. Other cancer-fighting gifts include:

In 2007, Mr. Koch was honored with the Double Helix Medal for Corporate Leadership from Cold Spring Harbor Laboratory for supporting research that, “improves the health of people everywhere.”
Education & Science

Mr. Koch supports science-related projects including funding of the long-running PBS documentary series, “Nova,” and a science and technology center at Deerfield Academy in Massachusetts. As the national sponsor of The Bill of Rights Institute's 2009-2010 high school essay contest, Mr. Koch's philanthropy helps educate young people about the words and ideas of the nation's founders. Winners of the “Being An American" contest were honored at a gala held in Washington, D.C.
Mr. Koch’s $15 million gift to the Smithsonian’s National Museum of Natural History in Washington, D.C., created the David H. Koch Hall of Human Origins that opened spring 2010. The 15,000-square-foot exhibit offers visitors an immersive and interactive museum experience. In 2006, he made a $20 million gift to the American Museum of Natural History, creating the David H. Koch Dinosaur Wing.
Public Policy

A passionate believer in free societies, Mr. Koch has funded research and education programs that analyze how freedom creates prosperity and advances social progress. He serves on the boards of the Cato Institute, the Reason Foundation and Americans for Prosperity Foundation.