Despite the downvotes, this is an accurate statement. There are 13g of sugar in 8oz of milk, which is half of what you'd get from a Coca Cola but still a fair bit of sugar.
It actually has more sugar than fat or protein. Quite a bit more.
If you dump 13g of sugar into 8oz of water, do you not have sugary water? If you then dump in 8oz of protein and fat, does it cease being sugary water?