Of all the crappy misbehaved children I have come across, not one of them was from parents who disciplined them consistently. They all had weak parents who were more worried about their kids liking them than they were about raising respectful, loyal, good children.
I totally agree with most of what you've said other than the quote statement. I definitely agree that with some kids, a parent is given the unfortunate ultimatum of either hitting their kid, or taking the risk of allowing them to grow up spoiled and misbehaved brats...
I've met a few really rotten people who were beaten relentlessly by their parents, and not necessarily for disciplinary reasons. These are generally the types of people that you need a weapon should you choose to confront them about anything...
... This is where the middle-ground between the Pro and No crowd is: beat your children for no reason and they'll become impervious to pain and beat the holy hell out of anyone (including probably you their own children) who crosses them as they get older; never hit them and use "time outs" and other such emotional (non fear-based) punishments that only work on submissive-type children and they may turn out rotten in one way or another anyhow.
There's no easy answer here because even light to moderate spanking becomes a joke to most kids once it's been done once or twice. But, ask old-timers and they'll almost always say that the strap kept them in line. I mentioned earlier that my dad smacked me in the face real hard, once, when it really mattered, and that smartened me up -- whereas, a grounding or taking something away as a punishment wouldn't have made a lick of difference to me personally.
It's all on a case-by-case basis and most parents don't have the experience they'd like to think they do in order to effectively say yay or nay. You'd have to raise hundreds of kids to really make an honest judgement call on this issue, as most studies favour the desired outcome (hitting kids is bad), rather than the honest truth of the matter (do it when it counts, not as a stress-reliever or because you enjoy it.)