To be fair I encounter that problem with other adults, too.

one of them screams about something that doesn’t matter

I mean, one of the challenges of child care is having empathy for kids who are still struggling to regulate their emotions. If you're openly dismissive and adversarial to kids, their behavior tends to get worse over time.

There are plenty of people who simply aren't mature enough, themselves, to know how to interact with children. That's one big reason why its helpful to have large extended family homes. Grandparents - particularly those who are retired, experienced, and nostalgic for parenthood - can be way better at dealing with little kids than adults who are themselves too emotionally congested and socially anxious to know how to respond.

But people routinely overstate how difficult child care can be, in large part because they fixate on the grumpy and frustrated children while suffering total blindness towards the happy, well-adjusted, and well-behaved kids.