Can you cite anything? I cited something that demonstrates the uncertainty and explains why it exists (difficulty of studying it, extreme variation among individuals).
There is no single, hard rule for nutrition yet. We don't even know how healthy milk and fish oil are. Vitamin D supplements were just shown to have no benefit for bone health. Exercise and amount of food play a huge role in whether a diet works.
You cited a magazine article. Just look at the recommendations that nutrition organizations give, WHO, etc, people that are experts in the field. If you think it's bs then there's not much I can do about that
My 2c to your response: there is some variation among individuals, I think it's intentionally exaggerated. Milk isn't a health product, but it's nutritious and useful for those that don't have much appetite to eat. Agree about fish oil unless you're deficient in omega 3. The amount of calories you can eat plays a huge preventative role in having any deficiencies. Most people have some kind of deficiency. Most people don't, or can't due to age or health issue, exercise so much that their metabolic rate is high enough (1.5-2x higher) to see those gains, which is why nutrition advice matters. If you ignore everything about nutrition, you can get the most benefit by avoiding added sugar and oils. It goes a very very long way