I guess if it is pastuerised or something it's seen as impure or processed and only farm milk straight from the udder is real milk?
Then again, I grew up with the one and not the other and hubby, who grew up with Rivella likes it but not rootbeer.
Near as I have sussed (and I could be - and probably am - wrong), the "Milk Drink" is lower fat than "vollmilch". General advice maybe to drink the lower fat milk and hence the "drink" label?
Correct. Milchdrink has about 2.8 % fat, whereas Vollmilch has about 3.5 % fat. The strange naming was introduced in the 1950's by Migros, when they launched a beverage called Chocodrink , made of skim milk and chocolate. I think it was the first beverage in Switzerland that was sold in the legendary Tetrapak cartons, I mean the real tetrahedral ones, not today's Tetrabrik kind.
Ever since, pretty much everything based on low fat milk in Switzerland has been called a drink. Motto: Main thing it sounds English, no matter how wrong.