It's been theorized that SJWism is a form of Puritanism, with their idea of progress only going in one direction and of there being a "shining city on a hill" that serves as a perfect, utopian example for others to follow. I don't know however, if Bob is capable of internalizing a concept this grounded in history. To Bob, societal "progress" is just like progress in a video game - once your character reaches a certain level, it stays there forever; it can't "lose experience" and revert back to an earlier one.