What is with the milk hate? Is it cool to not drink milk now?
1) Health nuts. As another poster mentions, many of the fad diets that have swept the country over the past 30-odd years have taken an anti-dairy stance. Milk loses. (Ancillary: breakfast cereal has been taking a big, big hit among health-conscious consumers, and as breakfast cereal goes, so too does the milk that goes with it.)
2) Crunchies. These people have various reasons (health, the environment, etc.), but regardless, they're against processed foods, industrial farms, GMOs, non-organic anything, and so forth. As the various horrors of factory farms have come to light, these people have turned away from milk.
3) Convenience drinkers. Water and soft drinks have edged out milk as a "snack" choice. They keep better, travel better, and to many people, taste better.
4) Kids. Kids have pretty much never liked milk, despite parents' best attempts to force it on them. This is because milk, as a standalone beverage, is revolting. As parents begin to question the purported health benefits of milk, they stop subjecting their children to it.
5) Trend takers. Not health-conscious eaters per se, but rather, the kinds of eaters who just know they can't touch gluten, despite never having been tested for celiac disease. These people take their cues from the health nuts and the crunchies. If you're looking at a food trend from a Crossing the Chasm perspective, the health nuts are the early adopters, and these folks are the followers. They don't set trends, but they'll never pass up the chance to hop on a new bandwagon. CNN said something about dairy, or paleo, or gluten, or whatever, and these people are now religiously opposed to those things. It's half identity politics, and half inchoate desire to make healthier lifestyle choices. In either case, it's half hearted.
6) Ron Burgundy. It's too damned hot. Milk was a bad choice.
That is a patently false claim.
Most of the modern "fad" diets are against dairy. Personally, I'm torn. I'm half-convinced that it's "unnatural" for human consumption, but at the same time it's a cheap, tasty way of getting good fats and protein.
Its not like a large portion of the Earth's human population has evolved the ability to process lactose after childhood or anything--
I can't speak for the specific case, but on a general guideline, the great majority of people can reap huge benefits simply by doing sports and dropping junk/processed food. In this perspective, choosing one food [group] over another, is nothing else than bikeshedding (in other words, the bottleneck is somewhere else).