The Gedney photo is easy to like, as are most of the photos in the series. It's more National Geographic, more uplifting, less comitting. We can look at these people's lives without any consequence to ourselves beyond what we choose to feel.
Adams' subjects don't just know they are being photographed. They know they are being pitied - and that they are being pitied for what they are rather than who they are. That makes them, and the photographs less likable.
Geoff Dyer's "Ongoing Moment" talks a fair bit about Gedney, but I still can't recommend it as a purchase. I think the author profile says he has co-authored a book about Gedney, but my copy is boxed up for a house move so I can't check. It might be worth a look if you don't have to pay for it :-)