@elperronegro Something very similar happened to me years ago, but in Madrid, not even rural Spain.
I had attended a professional workshop and at the end of it, there was a dinner. One of the participants was a vegan, and, as he was English and spoke very little Spanish, I tried to help him order a salad.
I specifically asked the waiter for a salad that contained “nothing that comes from an animal. Just vegetables: lettuce, tomato, onion... You know, vegetables.” It took them three tries to realise that boiled eggs and tuna actually come from an animal.
I have the theory (supported by many such cases) that most cooks do probably think: “Customers will either eat what I make however I make it, or nothing at all.”
@josemanuel Good story Jose and yes, I think your theory is correct