The only ones who benefit from drinking cow milk are calves. It’s made for them. The only good milk for human is human milk.
Almost no one will dispute that when a baby is born, breast milk is the best nutrition a mother can provide. All mammals nurse their young, and breast milk benefits a newborn infant in ways above and beyond nutrition. In fact, until 1 to 2 years of age, the American Academy of Pediatrics, the World Health Organization, the Institute of Medicine and more promote breast-feeding as optimal.
Unfortunately, breast-feeding until that age is often difficult, if not impossible, because mothers have to return to work, and children go off to preschool or day care. So we often replace human milk with the milk of cows or other animals. But at a certain point, we have to acknowledge that we are the only mammals on the planet that continue to consume milk after childhood, often in great amounts.