Despite what some appear to believe, there would be many exceptions to the rule. I don't personally know anyone my age that wasn't spanked a few times, when they were growing up. None of them feared their parents. As a mattered of fact, they all adored them, as I did mine. I wouldn't have traded my parents for anyone else in the world. I'm sure they all felt the same way. The ones with living parents are still very close to them.
As far as the idea that you wouldn't hit a pet, so you definitely wouldn't spank a child, I've never had a pet that could upset me as much as my DS could as a teenager. There was never a reason to hit a pet, but we never spanked DS either.