I've heard milk is hard to digest and mucus-forming. I seem to be a little lactose intolerant. I like Coke and Pepsi better. Reasons abound why athletes don't drink milk.
Some reasons are valid, some are questionable.
Milk drinkers have a better quality diet than non-milk drinkers. And people who drink milk tend to have stronger bones. Hence, if you are among the many people who think milk is for kids, you may be missing out on this very important mineral. Men used to have an average life span of below age 70, before osteoporosis became a problem. Efforts to prevent osteoporosis focus on ways to optimize bone density.