We really only need 10 to 15 percent of our total calories to be in the form of protein. If we exceed that, we put strain on our kidneys. We may be contributing to the obesity epidemic we are now seeing. High-protein diets seem to be a major contributor to low calcium. In other cultures, where people don't drink a lot of milk, they don't have some of the health problems that we do.
Balance is the key.
It is okay to drink cow's milk, but we shouldn't overdo it. The difference between two percent and whole milk probably doesn't make much difference in the end. It is probably a good idea, but they don't have to. If they are eating a healthy diet, then they are getting all the vitamins they need. The new growth curves are out.