"Drink your milk."
"If you don't drink milk, you'll get osteoporosis."
"You need milk to get enough calcium in your diet."
Sound familiar? We've all heard it, all our lives. That is, all of us in the U.S. at least, where the dairy industry has fashioned our food pyramid in its own image. There isn't anything quite so unnecessary in one's diet as dairy products. As one columnist recently noted in the mainstream New York Times, the prevalence of osteoporosis is actually highest in Scandinavian countries, where animal milk consumption is highest. And, of course, there's the fact that the majority of people worldwide are lactose intolerant (if milk is necessary, how are any of these people healthy and osteoporosis-free?).
Milk (as are all dairy products) is high in saturated fat. It's also (along with all dairy and meat products) exceptionally-high in protein. And, guess what a high protein diet causes? Yep, osteoporosis. Check out this article.
Ok, so that's one human-health aspect related to dairy. But what does all this entail, if anything, morally-speaking? Consider the cruelty of the dairy industry, for a moment, as depicted here, here, here, and, well, pretty much any readily-available sources (and there are many) you can check into yourself. Now, when dairy was necessary, and we all had to drink cow's milk as a basic facet of maintaining our health, one might, on pain of momentarily shunning their sense of morality, nevertheless argue that the practices of the dairy-industry, though bad, are necessary. After all, human health is more important than the health of other animals. So yeah, the industry is (sort-of) bad, but we need milk! Maybe, just maybe, we can work on making conditions a little better, if that will sufficiently mitigate our moral-culpability. (Except, that would interfere with efficiency of production, so precious when considering how our gallant U.S. dairy industry needs to deliver milk to its 300,000,000+ valued consumers, gosh all mighty!).
But, well, even this argument is untenable. Milk and dairy are unnecessary (and, it turns out, a net-detriment on human health, at least, for those who live in a society where all nutrients are readily available and in abundance). So all these animals are, in fact, living god-awful, painful, uncomfortable, wretched lives for no reason other than to continue making the dairy industry a profit. This isn't even cynical. It's reality. Better to face it and acknowledge it, better to understand it, than to ignore it and play a role in the perpetuation of animal cruelty (yes, actual pain and suffering- this is not an abstract phenomenon we're talking about) on a grand (indeed, the grandest) scale.