I really cannot believe that this kind of thing actually happens. It's so ridiculous. I was never one to breastfeed in public myself and always expressed, but I would have no problem with anyone doing it in front of me if they felt comfortable with it. It's the kind of thing that no-one would really notice when you're just sitting quietly, getting on with it. So why should it offend anyone? I could understand it if a mum was sitting topless doing it, or was breastfeeding an older child, rather than an infant, but feeding a baby when he needs it should be allowed anywhere. It's just common sense.
I agree that the security guard just had too much time on his hands and got a bit too full of his own importance. Good for the couple for standing their ground.