Its also pretty similar to human milk, which has evolved to be a close-to-perfect source of nutrition.
Biologically this means that the infant would release the mother so that they could have another child, so there is biological adaption on most species to not drink milk past a certain age.
And we have it too via lactose intolerance, which is normal.
However, some relatively small percentage of humans developed the ability to drink milk around 10k years ago in Turkey, but it's not perfect. It gets worse with age as one would expect.
Human babies shouldn't drink cow's milk, it's completely unnecessary and there are questions about it's effect on long-term human health.
https://www.snpedia.com/index.php/Lactose_intolerance and https://en.wikipedia.org/wiki/Lactase_persistence
And we know since the mid 2000s by a dozen or so genetic studies that these genes did not arrive from a single culture or single timeframe, but are an example of "convergent evolution" aka it was beneficial for humans generally and thus when independent random mutations occurred they persisted longer for those people were more likely to breed and thrive. This happened several times in human history and are not a singular event.
And thus individual humans may have Lactase Persistence in adulthood and other individual humans may not have the persistence. Furthermore how much Lactose you can process with the Lactase enzyme is a dependent process where some people can handle some quantities but not too much quantity of Lactose all at once.
But we're not animals. Animals cannot drive cars (not even the babies!) and we do. We're different than animals in some aspects.
Some of us are able to digest milk
Also, there is a whole spectrum to it. You don't have to be 100% medically diagnosed as lactose intolerant, it might cause you ocasional digestive issues without you even know it.
Like those unexplained, once a month or once every 3 months diarrheas that many of us take as a fact of life, it's actually not normal and might very well be dairy that is causing it for a lot of people.
At least, a lot of us do it a lot worst than we realize, and there are a ton of people with recurring mild digestive issues which should not be consuming dairy daily at all, but keep doing do due to the public perception that its a healthy thing to do when in fact it's not.
The ones that can digest it, do it usually less well than they think they do. Mild chronic diarrhea is prevalent is western countries, and a degree of dairy intolerance could very well be one of the factors.
It gets worse for most people with age, as elderly people can become lactose intolerant, fully or only slightly. This does not happen overnight, its a progressive thing, many people gradually stop being able to properly digest dairy.
There are also lots of dairy products that contain little lactose, from lactose-free milk to cheese. And of course, it's pretty simple to just take lactase pills.
From a completely subjective perspective, dairy products are some of the tastiest foods, and they're objectively a huge part of food culture in Europe. I don't foresee them going away.
But there is this perception that they are absolutely essential due to decades of dairy industry advertising and lobbying, and it's simply not true.
We are animals like all the others, even if a percentage of our population evolved the ability to continue to digest milk into adulthood.
There's an entire class of people called "children" who are neither babies nor adults who can benefit from drinking milk (or any other good source of calcium).
1. According to whom?
2. Can you name a type of food that has zero questions about its effect on long-term human health?
Globally seen yes. Locally it depends. Living in i.e Europe and having lactose intolerance is not normal.