I was a Doctor Spock baby
My children were Penelope Leach babies.
My grandchildren are @pinkymckay1 babies.
But my parents were raised without the influence of parenting books and experts. They were babies of The Great Depression, born between two world wars: their parents were trying to keep everyone alive. But my grandparents were born in the Victorian 1880s.
For these generations before the post-war Baby Boomers, the only parenting guidelines came from The Bible. And there was a lot "sparing the rod and spoiling the child" involved. And the experts espoused these values from the Church Pulpit every Sunday.
"Good" children were seen but not heard. Cleanliness was next to Godliness. There was a hierarchy of society and children came very low on the list. Early childhood was a period you had to survive and, once you did, you were considered more a miniaturised adult than a developing child.
Surviving that early childhood was not guaranteed in any way in the Victorian era. Infant and child mortality rates were high. The hazards of life were many and illness and injury were a daily threat. Drinking the water was risky - tea or beer were safer! Milk from cows could lead to disease and if a baby wasn't fed at the breast, survival was unlikely.
It probably made a lot of sense not to get too attached to infants and young children in such times , given the risk of losing them in the first five years. Even if a woman could control her fertility (most couldn't), numerous children allowed a higher chance of some surviving to care for parents in later life. They could contribute to the family income before marriage and establishing their own household. In poorer families, before laws were in place to protect them, even very young children were expected to do whatever work they could to contribute.
As each generation grows and become parents themselves, their childhood experience shapes their parenting style. Many vow not to raise their children as they were raised but this is easier said than done.
When your own parents or grandparents speak unkindly about or to your children, or criticise your parenting style, you might be hearing an echo of the past. Those Victorian doctrines were so entrenched they still appear in modern books, even if the language used is modified. If you have been told not to let your baby manipulate you; that your toddler just needs more discipline (ie: punishment) or a good smack never hurt anyone, you are hearing what those parents have learned.
Be gentle with the babies of the past. The trauma lingers and shapes their adult lives.