I dont know man. Ants are farming aphids for their sugary digestive secrets aka their shit. Bears eat Honey, which to all logic remains half digested bee-spit. Praying Mantis cut off the head off their mate after mating and eat it. Anglerfish males are not the mighty toothed beasts, but weird little parasites that nist themselves in the females and eat them from the inside until the female just lays its eggs before death.

So humans drinking other animals milk is maybe unique, but certainly not more weird than other ways of procurung nutrition, that nature invented.