How does the narrator arrive at his insight about who the gods of the dead places were

When John arrived at the city, he initially believed it to be a place of the gods. At the city, he discovers that it was in fact merely inhabited by men like himself: man whose world had been destroyed. This realization cleared his mind, and his fear disappear.

"When I woke in the morning, I was hungry, but I did not think first of my hunger for my heart was perplexed and confused. I knew the reason for the Dead Places but I did not see why it had happened."

"Then I saw the dead god. He was sitting in his chair, by the window, in a room I had not entered before and, for the first moment, I thought that he was alive. Then I saw the skin on the back of his hand—it was like dry leather. The room was shut, hot and dry—no doubt that had kept him as he was. At first I was afraid to approach him—then the fear left me."

"That is all of my story, for then I knew he was a man—I knew then that they had been men, neither gods nor demons. It is a great knowledge, hard to tell and believe. They were men—they went a dark road, but they were men."