I have a Facebook account that I barely ever use, and I would not use it to access free WiFi. That said, I can only side with the ice cream shop salesperson in

I have a Facebook account that I barely ever use, and I would not use it to access free WiFi. That said, I can only side with the ice cream shop salesperson in your anecdote. Just make a Facebook account with a fake name, use it when you want to. You seem more angry about the requirement of a Facebook account than not being able to use the free WiFi. But the fact is: if your goal is to use their free WiFi, you can do so without giving up your privacy (fake account).