My opinion is that they are good Mothers, feeding their children as nature intended. If someone feels uncomfortable-DO NOT LOOK! The breastfeeding mother and baby are doing nothing wrong, but it is wrong for people to think that something so natural is sexual. That is because of the prejudices in our own society.
Most breastfeeding mothers do so discreetly (you have probably "seen" dozens and not even realized it), and even if you do see some skin-you see just as much or more on the teenagers at the mall.
I find it disgusting that people suggest mother and baby go to the bathroom or their hot car, etc. If the mother and baby have a right to be there, the baby has a right to eat.
Most common complaint I hear is that protesters do not want to have to explain it to their children. Hiding it is why these people have these prejudices in the first place! Not explaining what breastfeeding is and why it is beneficial will only cause another generation to feel the same way. Seeing it as a normal function-the breasts ARE intended for the feeding of infants and not the sexual pleasure of men-will change society's view.
Common sense and research
Personal experience and opinion
Mom of two and one on the way!