I'm not a parent yet, but just through observation, I see discipline being only a minor part of raising children. The majority of who someone will one day become comes more from morals and life philosophy in general than smacks across the face or "time outs"
A lot of people with monstrous children have monstrous children because they themselves are idiots, shallow, anti-intellectual, with no cultural and moral foundation at all. Their kids are absurd because they haven't actually taught them anything, and believe people just become people naturally, rather than with direction.
This is why wealthy parents have kids who often do very well financially themselves, just as one example. Some people will EXPLAIN and EDUCATE their children on WHY an education is an advantage and provides a more fulfilling life experience, and others just tell five year olds they need to go to school to "get a job someday," like that makes sense to a 1st grader, because they themselves, not being educated, honestly have no clue how it enriches someone's life.
That said, even good kids can need a smack sometimes.
The knee-jerk freak out and ignore threats towards people defending "the spank" is just a little ridiculous.