Intentionally haven't read the thread.
I have never smacked DS (5). I am quite certain now that I never will.
I try not to judge many of those that do, but it can be hard.
I was smacked and worse. It was never about my safety, or a lesson, it was about my father's anger. I realize it is not that way for everyone. Anecdotally, I have no contact with him now as he is toxic.
Maybe I am very lucky because DS is well behaved for the most part, and respectful and kind. Before he was born, when DH and I discussed this issue, I thought maybe it could potentially happen, ie. If DS ran into the road. But in the years since he has been born, I just can't imagine myself ever harming him ---- my whole goal is to keep him from that, I can't fathom being the cause of it...does that make see? I honestly can't imagine hitting him would teach any kind of lesson, and for me personally, I'd hit about anyone else in the world before I could bring myself to hit him.
Anyway, suffice to say that for me personally certainly no, children do not HAVE to be smacked, to answer your OP. Parents, however, do have to have some method of asserting themselves to teach right and wrong, proper behaviour, and respect, which I think is where the debate has maybe started. I hope that this is not smacking. I REALLY want parents to be teaching respect, manners, and proper behaviour, using the best tools they have....but I have only one child so my experience is limited to that, and nannying and being aunty, so, really, what do I know?
All I know is I won't smack my child, and somehow he is respecf ful and kind anyway...but like I said, my experience is limited and maybe I'm just lucky. Best of luck to all.