The majority of humanity drinks milk and consumes other dairy products without bating an eye. However, once one considers the health realities and factory farming abuses involved in dairy production, truth illuminates dairy product consumption in an increasingly negative light.
Healthwise, throughout the animal kingdom, female mammals naturally produce milk to nourish their young directly after birth and for a few subsequent weeks. Humans are the only mammals who continue to consume milk and dairy products well past infancy. Not only that, but we continue to consume the milk of different species of animals, all under the guise that we need this milk and dairy to obtain calcium. However, in truth, humans can consume all necessary calcium via alternate food sources.
Furthermore, this unnaturally fostered dairy need puts excessive pressure on dairy cows. As previously stated, female mammals naturally produce milk to feed their young. Thus, they must be pregnant or recently have been pregnant to produce milk. Therefore, dairy farmers keep their dairy cows continuously pregnant to maintain steady milk production rates. This abusive, unnatural, year-long state of pregnancy puts immense strain on these dairy cows, pushing their bodies to their limits regularly all to give the human community milk they honestly do not need to survive. By consuming milk and dairy products, humans support this continued abuse.