Back in the old days (no, I mean way before I was a kid!), parents were very strict; children were punished for the slightest infraction of the rules. Some of us look back at outdated parenting and criticize those parents for being mean, harsh, even cruel. Other modern moms and dads want to emulate extremely strict parenting ideals--this is a personal choice, of course, but I think it's important to understand where the need for such strict parenting comes from.
I do not claim to be a parenting guru or a historian, just curious; I googled all kinds of variations of the basic question "Why were parents so strict in the past?" and everything that came up had to do with why modern parents are so strict about grades or why parents from certain cultures are strict. The underlying answer is that those parents want their children to be successful (good grades) and/or they want to keep them secure/safe from harm (restricting social media, rules about acceptable clothing, dating, etc). [Having successful kids means that they will have the capability of providing for their parents in the future, which is another kind of security.]
Here is my take on it: many years ago, children were expected to actively contribute to the household and had responsibilities, starting at a young age. Smaller children were required to do chores like weeding the garden or collecting water. As they got older, they were capable of doing more. (Of course, the most fortunate children were able to attend school, and were expected to spend a lot of time on "reading, writing and 'rithmatic".)
If a child didn't do his or her task as expected, he or she was punished. I'm not talking about a time out or a "consequence"; most of the time it was a spanking or some other type of corporal punishment. I think that the objective then, like it is now, was success and security--however, not the success or security of the individual child, but rather the success and security of the family unit.
Think about it: your child goofs around all day instead of collecting water, and there is nothing to drink, nothing to cook with, nothing to wash with. He doesn't shut the gate to the pasture, and you spend all day trying to round up your cows, hoping that something doesn't eat them. She is careless near the kerosene lamp and everything goes up in flames. Your very survival could depend on how you discipline your child.
In the 21st century--at least in a First World country--we don't have to worry so much about our kids jeopardizing our survival. Certainly, we admonish them if they get too close to the stove or fireplace, try to play with sharp objects or anything electrical, or if they unlock the door to the outside, but really, there are all kinds of gadgets we can buy to safeguard us and them against these behaviors. If you don't believe me, check out the catalog One Step Ahead and you will see what I mean.
Modern parenting requires safeguarding our children against a whole different set of dangers. We have to worry about someone else trying to harm our kids, and about them engaging in dangerous activities and harming themselves. Our idea of successful children (good grade, acceptance to the best schools, sports prowess, musical talent) reflects upon us as much as upon them, sometimes more so.
Let's take success out of the equation, since everyone's definition of that word is different. Let's focus instead on our children's security, which in our day and age means protecting them from negative factors, both external and internal. It also means teaching them how to be productive, conscientious, and contributing members of society. This is where Mean Mommy parenting comes in! If we take the time to carefully consider our parenting choices, then this is our end goal, no matter how we word it. The obstacles that might get in our way, the dangers, if you will, are not as obvious as running out of water or letting the cows run amok, but can still derail our kids' futures if we don't teach them what is important.
Finally, going back to the idea of success, if our children do turn out to be productive, conscientious, and contributing members of society, then we will have been successful, and they will have learned how to find their own success.