We need dairy products so our bones and teeth grow stronger
Why Do We Need Dairy Products?
Vitamins ( d, calcium) etc
We don't. We need a variety of nutrients which are sourced from elsewhere and only about 25/27 per cent of people on earth have dairy.
No one does, its just that they (dairy products) just provide some people with a source of proteins, fats, sugars, and vitamins & minerals. Many people go through their lives lactose intolerant, or else they simply choose different substitutes even if they can digest the sugar lactose, freely opting not to consume dairy or its byproducts.