What IS relevant is what a substance is designed to do, and how it is used.
Cows milk is designed to bring a baby calf to the size of a full grown cow in one year.
Mothers milk on the other hand is designed to bring a newborn manchild to a two year old child in two years, with 10-14 years still to go to maturity. That is a HUGE difference. Fermented milk products from milk that has NOT been homogenized or cooked can be health promoting for some people, but there are far better ways to get the same benefits. To each his own though.