Unfortunately, your opinion is in the minority. A lot of people (in reviews on on social media) really hated the in-jokes. We got dinged pretty badly in a few reviews.
Adding the option was a fun way to deal with it. As for why it’s off by default? It’s because from this point forward, most of the copies of the game will be sold to non-backers and people who are not hard core adventure fans. These are exactly the people who objected to the in-joke.
Unlike myself, players don’t tend to explore the Options, so many would never find it and turn them off. With the current method, If they find it later and turn it on, it will be like a little easter egg.