Eating dairy has been a significant part of many cultures traditionally. Whether cow, sheep, goat, buffalo, donkey or camel, humans have adapted to the highly nutritious milk of whatever mammals were available to us to domesticate. Cohabiting with animals has a long history. We have learned to store it, process it into butter, cream, yoghurt, cheese and other delicious and nutritious foods. 

Nowadays many health-conscious people eschew dairy for plant-based milks, but these do not contain the same nutrients or have much of a history. Plant-based milks are not necessarily better or worse, just different, but the ones we buy in cardboard cartons are often filled with fillers and emulsifiers such as carrageenan and are really a highly processed food with plenty of marketing.  

Why not just drink the mammal milk? I have read many reasons and I myself drank Bonsoy for many years, despite having a thyroid condition. I believed that cow’s dairy would clog up my lymphatic system and my arteries, and that milk was probably best left for babies. In reality, I get no negative symptoms at all from drinking or eating dairy, and it feels very nourishing for me now, and my thyroid is doing very well (the calcium in milk is good for the thyroid, but soy has some anti-thyroid properties). 

Not everyone is like me, and many people say they cannot tolerate dairy. 

This may have more to do with the state of their gut, rather than a problem with dairy. 

What happens when we stop drinking dairy is that we stop producing much of the enzyme lactase, which breaks down lactose, which is the sugar in dairy. Therefore it sort of ferments in our gut and produces gas and uncomfortable symptoms. We could just buy lactose-free milk but the lactose has a role in helping the calcium in milk get well absorbed 

If you have these symptoms and would like to be able to tolerate dairy better, I suggest that you start with small amounts- a tablespoon of milk with a meal. Increase a little each day. Most of us can start producing the lactase enzyme again in our stomach. Also, cheese is more readily digested by many people and that can be a good place to start. 

Others find they are allergic to casein, the protein in milk. This is a different issue. Many people find that the type of milk they drink makes a difference, and goats milk or A2 dairy, or dairy from other animals such as sheep, camel or buffalo, if you can get it, may be better tolerated. 

Others just don’t care for milk or dairy. Fair enough. 

Another reason for dairy being disdained by many is that it contains saturated fat, which has been wrongly demonised in the last decades (before that, saturated fat was pretty much the only fat people ate). The fat content also makes whole milk a fairly high-calorie food, but this is not actually a problem as it is very nourishing, and calming for the nervous system. If the fat/caloric content bothers you, you can always drink low-fat milk. 

For those who enjoy it or would like to, I recommend you get good quality milk, and support your local dairy farmers, especially those using best practice such as organic and grass-fed, even raw. However in Australia, pretty much all our milk comes from grass-fed cows, unlike in the U.S. And most farmers do love their cows and take good care of them. So your everyday Australian supermarket milk is not too bad either if cost is an issue. 

Dairy is a highly nourishing food group for those of us who enjoy and can tolerate it. And many of us could do with more real nourishment. 

http://raypeat.com/articles/articles/milk.shtml

https://katedeering.com/2013/09/got-milk/