I’d forgotten this little quirk of India. It truly shows how cultural norms define the language and interfaces of a country. In India a country which largely (espouses – opposite) the eating of meat, the question you are asked is “veg or non-veg?” The defining paradigm is therefore the addition of meat, not the subtraction of it from your diet.
By the way the best answer is almost always veg unless you are in an area like Goa, as the food is just so much more varied and finely spiced. Truly exquisite and no need at all for meat.