Earlier quoted context omitted.
It's beyond antisocial. Being forced to smell and see food, and watch people eat can be disgusting. Some food is obviously worse than others. Deliberately inflicting it on an entire office is not-so-subtly telling everyone else that their eating at their desk, rather than use any provided kitchen or dining facilities, is more important to them than their consideration of every other person in the place. It might be "…
You'd get more sympathy without the "its for their own good" part.
The point about it being for their own good is separate, but still valid. Too many people end up with long term health problems from sedentary jobs, and a small amount of physical and social activity at lunch is all some people get. Missing that out can be quite detrimental in the long run, from depression, lack of motivation and migranes to bad circulation and consequent RSI problems and other health problems.
I've suffered from some of the above even with not eating at my desk and taking breaks. Some of the people I've known who basically didn't move for 9+ hours a day had some horrific health and mental problems, and because people often minimise the dangers I'm deliberately bringing them up. They can creep up slowly over the course of years, which makes them insidious and underestimated. Being "so busy" you rationalise eating at your desk is symptomatic of a more general lack of care which needs sorting out.