Milk is for babies. Cows' milk is even weirder because it's for baby cows.
For some reason back during the mid to late 2010s Peterson types tried to make milk manly and cool again. I guess it was to make fun of soy, the misconception being that soy is 'feminizing' or some other superstition that's long been disproven (also, bro, cows milk comes from cow boob and is full of actual mammal estrogen so it's probably more feminizing than soy anyway.)
But old-timey people knew what was up with milk. Milk is lame. Milk is for babies.
you just unlocked a memory of that one scene in Pumping Iron where someone asks Arnold if he wants some milk and hes like "babies drink milk, men drink beer"