Smacking IS physical abuse. It doesn't make parents who smacked when that was totally normal anything but a product of their time, any more than people who thought black people were stupid or women were incapable of being raped within marriage were. But if you hit someone, you are physically abusing them. If you did it to an adult, you'd face criminal charges. Do it to someone completely defenceless, and that's fine? That makes no sense.
And justifying smacking on the grounds that it's better than psychological abuse is just odd. All abuse is bad. All abuse is wrong. If you can't say it's a fair and reasonable thing to beat someone far smaller than you, over whom you have almost total power and control, then perhaps that means people should not be doing it. Full stop.
There are stories I could tell you that would raise the hair on your neck. I won't say I've forgotten or even forgiven but I have learned to accommodate it, to understand that he was a product of a particular set of circumstances and he hated himself for his actions too. That is growing up.
I don't disagree with that. But nor are you saying it was a good method of discipline and that it was character-building and never did you any harm. There is a difference between understanding the humanity and fallibility of the people acting as society tells them they may, and condoning what they did. Smacking did harm me, because it made me anxious and scared of my mother. My mum herself says she struggled desperately as a single parent with one child on the autistic spectrum and one NT one, and she smacked when she lost her temper and coping ability. It was horrible, it was scary, and it was not a useful discipline tool, because she hit, as parents do, from anger. It wasn't good at explaining what was wrong in the behaviour, or instilling self discipline and self-control, which is, surely, what you want with kids?
And really, I return to the core point: why do people think violence is always wrong... except when targeted at the most vulnerable members of our society? That makes no sense whatsoever. Why is the ability to be violent to small children so important to some people? Sorry but I find that genuinely disturbing. Of course they drive you crazy and of course the temptation to hit is there. But it's the need to pretend that the urge towards violence is anything but very wrong, no matter the provocation, that troubles me. Why do people want to hit little children, and then feel good about that?
Either violence is wrong, or it isn't. And if people can't even accept that a blow intended to cause pain is violence, then their level of denial is extraordinarily high. And I also question why that is, if they're so sure what they are doing is not wrong?