It does sound a bit confusing, but basically processed cow’s milk is digested differently than “straight” cow’s milk. I’ve even seen older children who break out in hives to plain milk, but can eat cheese or yogurt. The milk in formula is processed and somewhat more broken down as is the milk in cheese, yogurt, etc. You see the same thing in other foods like eggs. Babies under 1 shouldn’t be given plain eggs, but do fine with bread and crackers and hamburger which contain eggs!