Failure to read the room might explain why the tourists persist in the questioning beyond politeness, but not why they embarked on the quest to interrogate the worker to begin with.

My family does this and I can barely go anywhere with them for the embarrassment. Everything is an interrogation. They actually take delight in the waiter not knowing the answer to where the seafood was caught, and then lecturing them about the importance of knowing such things (this is the most common one they pull). That's not just failing to read the room.