It's remarkable how quick people are to criticize Firewatch for not resolving Delilah's conversation that you overhear near the beginning of the game, considering that the story is clearly trying to tell a mystery story, and by definition mysteries need red herrings. Are we going to criticize Raymond Chandler stories for leaving loose ends now? Are we going to criticize The Big Sleep because we never find out who killed the limo driver, or why? Are we going to criticize The Big Lebowski because the Larry Sellers storyline goes nowhere? Or because it turns out Bunny was never kidnapped?
Criticizing a mystery story for its red herrings is like criticizing a maze for its dead ends. If there were no dead ends, it wouldn't be a maze.