Because some people chew with their mouth open or have other disgusting eating habits. If the train stops short, someones food may end up on someone else's shirt or all over the floor or seat, where it is left for the next person to sit or stand in. What smells good to some people nauseates other people. People who eat on subways tend to be pigs who leave their garbage behind. They also tend to be really fat, which makes sense given their inability to control when and where they eat.
BTW, I am a diabetic and I have never had to eat a bowl of spaghetti, a meatball hero, three slices of pizza, or a KFC extra crispy dinner, while on the subway, to control my blood sugar. I do carry a granola bar, glucose tablet, or small juice box in case I find myself in a difficult situation, but I have never had to pig out on the subway because of low blood sugar.
Lucky for you.I have extreme lows and don’t hve the abiltiy any more to always recognize when they are in the early stages.I am not type 2 as the majority are and it is different for us type 1’s.I do carry juice box wth me but with a no eating policy I assumed this was forbidden too? My point was that perhap this person was carrying their dinner home with them when they may have felt bad and went a head and ate?