Well I would like to summarize the airliners behavior as greed. Loosing one seat will of course mean one passenger less on the plane. But are all flights filled to the limit?

Some empathy shoul be expected!
BUT then there is a problem if the passenger does not fit into the seat. Donīt seats have arms? I have no idea how you would handle that. Of course not many people would tell you to your face "Iīm sorry but you do not fit into our seats". That would be rude and embarrassing. Of course the treatment she got from Delta was nothing more than utter degradation! If it is discrimination or an act of humiliation I am not certain of.
Note: I am of course not talking about Mrs. (Ms?) Edelmans obvious embarrassment. Rather that the airline did everything possible to sway her decision, thereby purposely humiliate her.