As annoying as you may find it unfortunately it is absolutely necessary for some people. Our 9 year old has celiacs and within 20 minutes of consuming gluten is in incredible pain. Not interrogating people about food when we eat out is not an option.
If anyone has a misconception about good manners it's you. My Grandfather, who is 96 and is now confined to a wheelchair, still insists woman and children precede him through doors and out of elevators. It's the mark of a true Gentleman imo.