I just finished reading yet another thread about rude behavior towards overweight people.
Below is a rather long excerpt from a book by Paul Theroux. He says that people doing solitary, healthful activities seem to be targets for bullies. He says this is part of our American culture of violence and suspicion towards others who are doing something just a bit eccentric in the eyes of a bully.
Being female makes us more vulnerable to bullying by men, anyway. When a woman of size is proudly marching down the street, or jogging at the track or cycling around the neighborhood, she is doing something unusual and somewhat threatening to what many men see as the status quo. To put it another way, a group of young men cruising around eating fast food and possibly drinking beer are feeling the strength in numbers that it takes to turn them into a small, mean mob.
So, in some cases, I think rudeness towards a woman of size may not have to do so much with her size, but with her attitude and the activity in which she participates. If she were different in some other way, that difference would be the reason to harass her.
Anyway, read this. It's interesting.