Once upon a time in America and elsewhere, rickets was too common until they found that ensuring a daily amount of milk to children reduced that debilitating disease and promoted healthy skin, teeth, and bones.
Eggs were attacked in the same fashion and then someone or some entity decided its okay. The same with pork, when it used to be as cheap as chicken - now it is popular again, advertised as the "other white meat" - referring to poultry.
Who makes up these rules?
As this article states - the government is behind high prices of milk, is that their greed for kickbacks?
Farmer families eat and drink those products that are bad for you, and statistically they live longer than others - or maybe they just exercise more.