Social standards are not the benign excuse you think they are. If someone ever hits you, you hit back. If that’s how they think you learn, then make them learn that getting hit hurts, and show them why they shouldn’t be hitting.
Letting someone hit you just cause “it’s normal” is called Stockholm Syndrome, and is objectively worse than being the one that’s doing the hurting, because it teaches other people that hurting others is okay.
If you saw an adult, hitting and dragging away a child who’s fighting back with all their might at a grocery store, there’s 2 things that could be happening. A.) just a parent “disciplining” their kid, or B.) a literal kidnapping is taking place.
In your (clearly more informed) mind, it would always be scenario A, and you wouldn’t even think twice about the possibility of scenario B, “because that’s the social norm,” according to you.
I’ll say it one more time: IF YOU THROW HANDS, EXPECT TO CATCH HANDS, NO MATTER YOUR AGE, GENDER, OR FUCK ALL.
It seems like you’re talking about what you think ought to happen rather than what actually happens. I’m not saying that social standards are correct in a moral sense but rather that they do objectively exist and control most people’s behavior. Maybe the world in which people usually did fight back would be a better world than ours, but it isn’t our world.
As for your specific question about the screaming child: the chance that it’s scenario A is nearly 100%. Public kidnappings like that do happen but they’re very rare. (I think that in practice, people would ignore a woman doing it but sometimes intervene against a man doing it.)