Most humans are lactose intolerant because they are not a calf. Humans are the only species that drinks the milk of another animal even after they are fully grown adults. Cow’s milk is designed by nature for calves to nourish themselves until they are fully grown. But we decided to breed cows, rape them, steal their babies and kill them, so we could drink the milk that we don’t even need. You may choose to ignore this, but this is the real science behind dairy. Lactose intolerance is perfectly normal for humans, and scientifically speaking, we do not need cow’s milk. Period.