The quote is from the closing paragraph of the interview:
Q: What can we learn from David Foster Wallace?
A: He's not a cautionary tale about flying close to the sun. His story is much more about an insistence on never being content with who you are or what you've written.
Here's a guy who could have been a well-known literary author and lived in his little literary persona. Instead, David insisted on trying to reach people in this highly unusual and emotional way and show people, as he does in that Kenyon College speech, that he cares about them and how they live their lives.
For a guy like David who wasn't naturally caring, this shows that you can push the edges of your natural comfort zone in order to reach people.
Another lesson is that often it's the simpler truths that carry you forward, and the complex truths that hold people back. If you can simplify what you're here for and who you want to be for people, you can achieve far more than if you insist that life is so complicated.