For the emotionally stunted, let's give an example

Imagine you were really excited about this food your were going to make. It's your favorite recipe, no one can make it like you, and it takes literal days of work to prepare (there's dough to proof, fermentation, a bunch of things that take a lot of time to come together). You put all this time and effort and sweat and pain into making it. Your hands cramp from kneading dough, your back hurts from bending over the counter chopping veggies, and you're mentally and physically exhausted after a while. But you know it's all worth it because you will get to eat the best food, you'll have made it yourself, and you'll have leftovers to last you as long as it took to make. The whole time you are just thinking about the potential of this meal that you're working hard to make, and you can't wait for the time to arrive when all your work pays off and you get to eat your favorite food.

Now imagine, you're almost done with the process, and then something goes wrong. You find out the milk in your recipe had gone off and made the entire thing inedible, for example. Now all that days of work, all the labor and pain and anticipation was for nothing. Not to mention, the bites you took while making the food have now given you food poisoning, so you're sick because of it too.

Yes, you could buy more groceries and, once you're no longer sick, start over and try again. After all, you still want this food. But, imagine how emotionally draining that would be. Imagine your disappointment and sadness at the loss of the food and the wasted time and effort and money.

Now... take that sadness and disappointment and multiply it by the amount of sadness you'd feel at the loss of an immediate family member you loved dearly. That's the kind of emotional devastation we're talking about here.

Its basically telling women that are emotionally struggling with a miscarriage that their feelings are invalid. I'd be willing to bet that person is not a woman. During pregnancy you start feeling attached to your child, even if its not born yet. So a miscarriage can be downright traumatizing and cause major depressions.

The amount of pain depends on the circumstances, but "tiny bit" doesn't come close to the reality. There can be a lot of physical pain, but there is also a HUGE emotional component that comes with it and will linger a lot longer than the physical pain.

My wife and I experienced three. There is a period of mourning because it does feel like a loss, especially for her.