You're going to get as many opinions on this as there are members. But to start, you have to define what you mean by "dairy" - and what others mean. Some mean cow's milk, some include the milk of other animals. Some are anti-dairy because of the additives; some by the conditions in which cows may or may not be kept (crowding, hormones, antibiotics). Some promote raw milk without additives; other authorities are concerned about bacteria in that.
You can consult a nutritionist - but you'll get more opinions if you consult 10 or 20. Someone below references the Weston A. Price Foundation, but others will tell you that the WAPF has been discredited many times over for dangerous positions not based on scientific research. I work with food scientists who wouldn't believe a word of what they say and there are journals that have apologized for publishing some of the Price claims which turned out to be unsubstantiated or falsified. (Price was a dentist in the 1930s so some say he had no credentials for dietary ingredients anyway.)
So if you investigate any legitimate sounding foundations and institutes, make sure you really dig. It's easy to discount the blogs that just repeat stuff from other sources (with or without investigating), but a lot of foundations with an agenda do the same thing. On the flip side, the Dairy Association clearly has an agenda which is to support the dairy farmers.
One place to find scientific papers is PubMed.com which is the clearinghouse for thousands of scientific papers produced by many research institutions and universities receiving government funding and private as well.
The other problem you have to face is that many people have negative reactions to dairy, not because there is necessarily anything inherently wrong with the dairy products themselves (once you correct for additives and so on), but because they already have a sensitivity. That sensitivity can be due to a variety of things, including epigenetic changes in themselves or their parents. Epigenetics is a very promising field which has a lot of potential answers for this incredible rise we are seeing in allergies, autism, food sensitivities, and autoimmune diseases as well as behavioral issues. There's tremendous research on it (you can find a lot of it in PubMed) and much more coming. A lot of it has to do with medical conditions (cancer, etc.) but much of it has to do with diet as well as things like the long-term effects of trauma and stress on cell function. (Epigenetics controls cell functioning and gene switch on/off which is reversible and which is separate from unchangeable genetic issues). You can research that in Science Magazine, Time, and other investigative articles that are at least written for the average non-scientist. So epigenetic changes that make some food intake uncomfortable or even hazardous is quite different from the food being dangerous inherently.
So as you research, ask those questions and define your terms.