Peter Grant grew up reading very different material than I did. He read the New Yorker, travel writers, creative non-fiction. I grew up reading sword and sorcery, the more escapist the better.
Thomas Wolfe said that creative non-fiction supplanted novels as the font of all wisdom about the world.
He doesn't differentiate deeply between journalism and creative non-fiction, holding creative non-fiction to a higher literary standard with the same core of fact. More widely, creative non-fiction needs to meet four criteria. It must be:
1. Must be based on real life.
2. Must be deeply researched.
3. "The scene" The context of events
4. Must be literary, have the style of literary prose.
The issues investigated in creative non-fiction provide the central motivation for the people, the characters. You let them emerge as you tell the stories of the people. It's about investigating a community, worming your way in to find the way the threads weave together.
In a way, that's what all literature aims for, though some genres focus on micro-communities (romance, and couples) and some try to tell the stories of entire worlds (high fantasy, like Tolkien or Carey).
Grant says that he's very aware of place in his writing, and place is almost always about people.
A considered speaker, he seems most comfortable relating stories already written down, stories about other people. Hearing him speak, it's easy to see how he's drawn out other people's stories to put on paper.