A lot of reasons actually. It isn't a "check of a statement" either. It is actually a widely debated issue.

Humans who can digest lactose after age 4 to 6 are actually mutant strains of humans. It isn't normal to be able to digest lactose after childhood. Everyone who is lactose intolerant is a normal human being, everyone who can is the "different" strain.

Also, our cows are pumped full of hormones and antibiotics. Those are found(in trace concentrations) in the milk we drink. It is believed to be a major contributor to the decreased age of puberty for both genders.

Also, there is absolutely no conclusive proof that milk helps fight bone loss. There isn't even good data on how the calcium is absorbed from milk ingestion.

The milk companies just get a TON of government subsidies and try to keep the public persuaded that it is a good thing. The dairy industry spends a lot of false advertisement campaigns.

Just look at there adds. They say things like "3 out of 5 kids dont get enough calcium and iron"- true and things like "milk contains calcium and iron"-also true. But there isnt proof that the calcium and iron in milk actually helps those kids who are deficient in any way. If it did their adds would say something like "3/5 kids who dont get enough calcium amd iron could get it from milk".

They dance around that statistics on their adds. Because there is no proof that you absorb it well.