Clue 6

So Ellison is 37 when he finishes writing the book.

He's about to emerge from his hole with his novel complete.

The narrator somehow realized a power in that act of writing. She has a rape fantasy. He chooses not to commit it, but instead writes that Santa Claus did. He then panics and erases his false confession.

Santa Claus isn't real, it's something children believe in. It's as fictional as the black men that everyone sees in the narrator but isn't really him. So he writes (and then erases) that a fictional character assaulted Sybil. Why causes him to erase it? Does he decide not to 'agree with them til death and destruction?'

Maybe one more clue.

Clue 7