Except etiquette extends beyond just “common social etiquette”. Using a knife and fork the “correct way” is etiquette. Eating soup by scooping the spoon away from oneself is etiquette. Placing your cutlery the correct way on the dish when you’re finished is etiquette and varies wildly by country. These are just examples of dining etiquette, there’s much more. Its all bullshit and I agree it should boil down to being respectful and mindful, but depending who raised you it may happen that you get reprimanded and punished for not following very arbitrary rules.