Yeah I'm not sure what the adults were thinking in that situation. My guess is they weren't thinking at all. They knew I was into sci-fi and space so maybe they thought it was just going to be a cool sci-fi space movie.
Who knew there would be monkey murders, creepy voyeuristic killer computers, and giant space babies?
I did, and I enjoyed it, and in fact the original movie became a bit of an obsession for me. I watched a video that explained the meaning as related to tools and man's use and relationship with them.
I can't find it now, but this article gives a good overview of the concept with quotes from Kubrick backing the idea up. I'm still a pretty faithful Kubrick fan, with exceptions.