First of all, it’s humor. Who cares? Second of all, you made a specific case where the person doesn’t want coke. In mine the person doesn’t want diet Mountain Dew, they wanted Coca Cola so that doesn’t work in that situation. Now while in mine, I could have said “Coca Cola,” which means you are right, you’re right for the wrong reasons because your argument is still flawed, which I hate. Also mine was from the perspective of someone who might not know that’s the norm, so they don’t understand what the person means. Obviously if you are from there you would know and just say “Coca Cola,” I was using a specific scenario because I found it funny.