We shouldn't drink milk at all, it's unhealthy, it's only for babies.

Milk is designed to make a 100 lb baby cow turn into a 1000 lb adult cow. And we wonder why we have become fat

Not to mention cow poop is a common and allowed ingredient in pasteurized cow milk (as long as it is not in large doses) source

I dont tthink people are talking about infants as much as fully grown adults still drinking something designed to fatten baby cows by 900 lbs.
+ the only reason dairy is such a big part of our food pyramid is because three of the creators of the food pyramid were working in the dairy industry