A still from the movie Demolition Man in which some police officers prepare to confront a character played by Wesley Snipes.
Top Text: Demolition Man: A movie which depicts a horrifying dystopia...
Bottom Text:...in which food is too healthy, bidets are common, and cops literally don't know how to assault a black man.
The joke is mystery, like duh, the conversations about how to use it were relevant. No human in the US had anxiety over bidets. When conversations about the sea shells were had, they involved the physical use of them specifically.
Bidets weren't in the zeitgeist. When people engage with the sea shells (the literal and exact intention of the sea shells was to wonder how you use them), they thought about how they would physically replace toilet paper. The scene literally shows you the main character generating paper to use.
Like it's crazy I even have to note this, when you hear hoofbeats in Wyoming, you don't wonder if zebra are making them.