Although I agree with most of what you’ve said I don’t agree with this part. I have a nut allergy myself and it’s a pain. Every time I go out I have to ask the waiter to check if there are any nuts in the food. I expect the establishment to know what is in the product they are selling me. If they don’t know or the information isn’t available I’ll order something else or go somewhere else. It’s the job of the restaurants to train their staff properly as there are many people with allergies and other dietary requirements. I haven’t seen the video so can’t comment on this guy’s reaction but if his son has a life threatening allergy I’m not surprised he was annoyed.