If you don't specify well, then if gives you the most generic stuff. Based on your summary, it's a good answer, what did you expect?
I'm certain that if you ask ChatGPT to interpret the symbolism of another movie with a different and benign underlying theory, it will even come up with some ideas on its own. However, it will refuse to do so for The Shining and the moon landing.
I got one subtle reference. I think it's safe to assume that if your prompt only mentions the moon hoax and Shining concepts with equal weight it doesn't know which one you are more interested in. So if one has some misconception in it, then it makes sense to correct you more strongly. Also, LLM-s aren't manipulating you, that requires intention which they don't have.