I should have truncated the quote from you to make it clearer so I apologise for that. I agree of course that human milk is better for early infants than cow's milk or formulas, until weaning.
My objection was to this assertion, not the rest:
which is not supported by nutritionists. For example, see below from McGill University. No suggestion here at all that adults or children shouldn't be drinking cows' milk, in fact it is recommended as a valuable nutrient resource.
Consumption of Milk and Alternatives and Their Contribution to Nutrient Intakes among Canadian Adults: Evidence from the 2015 Canadian Community Health Survey-Nutrition. Auclair et al Nutrients (2019) Aug 19;11(8):1948.
Abstract
As a staple food and dense source of nutrients, milk and alternatives play an important role in nutrient adequacy. The aims of this study were to quantify the consumption of milk and alternatives within Canadian self-selected diets and determine their contribution to intakes of nutrients and energy. [...] Milk and alternatives contributed >20% to total intakes of calcium (52.62 ± 0.46%), vitamin D (38.53 ± 0.78%), saturated fat (28.84 ± 0.51%), vitamin B12 (27.73 ± 0.57%), vitamin A (26.16 ± 0.58%), phosphorus (24.76 ± 0.35%), and riboflavin (24.43 ± 0.37%), of which milk was the top source. Milk and alternatives contribute substantially to nutrient intakes and thus warrant further attention in terms of mitigating nutrient inadequacy among the Canadian population.
https://pubmed.ncbi.nlm.nih.gov/31430962/