In humanity's history, people were routinely ostracized, beaten and killed for deviating even slightly from a strict set of norms, including family members. Imagine you are a new mother and are deeply depressed, or worse yet even have hateful thoughts towards your child. How do you think fiercely patriarchal societies would deal with it if you spoke out? Or your husband/boss? Just because people are more outspoken about their personal experiences now does not mean those experiences are some "sudden" phenomenon.