I recommend reading the article in full, but here are the main points of this argument:
1) cow's milk is meant to fatten up baby cows, not humans
2)natural and synthetic hormones given to cows can interfere with our own hormonal function
3) most cows are fed inappropriate food - this is relevant because it means that most cows are chronically ill, and therefore require lots of antibiotics to stay alive, and producing milk.
4)dairy is acid-forming (too much acidic food is thought to demineralization the body, and contribute to lots of disesases and nutritional deficiencies)
5) countries where people eat the most dairy have the HIGHEST rates of osteoporosis (hence, our justification for eating dairy for the calcium doesn't seem to actually help!_
6) dairy cows are poorly treated, and often sick animals living in confined spaces
7) pasteurization kills the good stuff in milk, and makes it harder to digest - causing more allergies
8)dairy is mucous forming - not ideal for those with frequent colds or allergies
9)dairy consumption has been linked to arthritis
10) homogenization makes it harder to digest - more allergenic
11) pesticides in the cattle feed make thier way into our dairy
While I would agree with all of the above points, which can all be substantiated by nutritional research, I do not recommend that everyone stop eating dairy.
Many of these problems come from the way the cows are raised (on industrial scale feedlots and dairy farms), and how we process the diary products. The solution, therefore, is to seek out organic dairy products, which will mean that the farms where the milk is produced have met much stricter standards for operation.
Under new USDA Organic laws (relevant in Canada as well), dairy cows must have access to pasture daily, which means these cows will be eating more of their natural diet - grass - which will in turn mean that the cows are healthier, and the milk is more nutrient dense. Dairy, and beef from cows that eat a grass-fed diet are no where near as acid forming as conventional diary and meat products. In fact, they provide omega 3 fatty acids, which are anti-inflammatory, and health promoting.
Organic also means that the cows are not being given antibiotics or hormone treatments - which wind up in our milk from conventional dairy. Organic means the cattle feed is pesticide and GMO free, which also make our dairy products more healthful.
So while you will find that buying organic dairy products is likely pricier than buying conventional milk, cheese and yogurts, I would strongly advocate for realigning your budget to make this possible. Dairy products can be health supporting for children and adults, when quality products, sourced from good, organic farms are consumed in moderation.