I manage a store at a mall. I've seen them put a nursing baby on the counter, while still nursing, and proceed to talk on their cell phone. I've had mothers come into our store{a very small store}, sit down in one of our customer chairs, proceed to nurse the baby, and ask to look at merchandise. I've seen mothers nursing their baby at the bar in a restaurant while the TV and music is blaring and they have a beer. I actually had a mother hand the baby to me in the middle of nursing so she could talk on her cell phone{she knew it was not an emergency call} and talk for sevral minutes while the baby fussed in my arms. I've had mothers with very tiny babies come into our store in the middle of snowstorms just before closing at night. I even had a mother leave her baby in the car carrier on the floor of my store while she ran out to her car, with the admonishment to please watch him. I could go on and on.
I don't care whether they happen to expose a breast. I do care that they seem to have the idea that breast feeding is simply giving the baby milk. Are all mothers like this? Of course not. But there are a lot more than you realize. You sound like a responsible and loving parent. Unfortunately not all are the same. And just because they are breast feeding doesn't change that.
I agree all those incidents you mention are horror stories and those mothers are being selfish. Hopefully they represent only a small minority of mothers who need to nurse in public places.