It’s not?
I almost never got any physical discipline, but I knew my parents weren’t afraid to use it. Just that thought I think helped kept me from ever getting it much.
I can only remember once that involved my dad - as well as a gauntlet of my aunt an uncle who spanked all us cousins for an incident (rather minir, too).
The only other spanking I can remember was from my uncle, along with his sons my cousins, in their house. That was a little naughty.
BTW, I was never a “rebellious” teen, either. I guess it worked.
When objectively analyzed what is generally found is that people who attribute their adult ethical behavior to spanking are actually confounding general good parenting with hitting. I suspect that your parents did a lot of other non-spanking interventions in your life, most of them positive. Not the least of which would be loving each other, working for the family (the institution itself), setting standards and expectations and giving responsibility along with consequences - both good and bad. That’s how you build a good person. No spanking needed.