Blood Meridian's narrator is not an authorial voice that exists outside the narrative. The narrator is Judge Holden himself.
The narrator is Samuel Chamberlain's spirit form, possessing Cormac's mind. The Kid is Chamberlain. The kid didn't murder or rape any children, and the Judge was never in the outhouse; the only thing left in the outhouse was the spirit of the kid and about 80lbs of cowboy shit. The man lived happily everafter.