I used to breastfeed my babies in Target all the time - IN THE DRESSING ROOM. Where I had privacy, time alone with the baby, plenty of room and a place to sit down. I really don’t see the upside to nursing with one arm while pushing a cart with the other, unless you have a totally pointless point to make.
But you didn’t have a baby to gain a prop for political theater.
I have always thought they should make a baby room in the stores. At least I would do so if I were going to own a business especially a store. They already have two restrooms and dressing rooms. They could have a nice room with couches, changing tables for diapers, a sink, and other needs. I think this would be a great marketing tool and people everywhere would appreciate it.