Nutritional science has gotten a lot of things badly wrong, so it plays second fiddle to how I feel when I add or remove something from my diet. I've tried on a few occasions to cut dairy from my diet. It was sub-optimal.

  Most humans can't digest lactose after infancy [1].

That source: "Approximately 65 percent of the human population has a reduced ability to digest lactose after infancy."

"Reduced ability" != "Can't"

>Most humans can't digest lactose after infancy [1].

Here (Europe) most can. So it's normal to digest lactose here. In other words, yes percentage wise you are correct. But is's not equally distributed.

Some people die from being near peanut dust. That doesn't mean nuts are unhealthy to those who can eat them.

Even those who are included in "lactose intolerant" populations actually have no trouble chugging a huge glass of milk everyday along with some cheese and yogurt. Intolerance charts like you'd find on Wikipedia would lead you to suggest east Asians can't consume milk at all without discomfort, yet yogurt for breakfast, milk during lunch, a milk tea before dinner and ice cream after isn't even the slightest bit uncommon and causes no trouble for most people.

That some people can consume liters a day (or gallons, for those trying to gain muscle fast) seems to indicate that some people evolved to be fine with dairy.

I wonder how skewed this number is in the US due to doctor's notes for (un-needed) school lunch exemptions, assuming the note got charted (which is basically mandatory with electronic records). Even when I was in school, (before allergies were cool) a large number of kids faked it for access to the alternative menu, or to be allowed to bring their own lunch and snacks. I suspect it's only gotten worse.

In the overall US population peanut appears to be the most common, 58% more prevalent. In children, milk is far and away more common, 220% more prevalent, but many milk allergic children outgrow the allergy.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4254585/