There is never, ever an excuse for striking a child. It is bullying, plain and simple. How do you feel doing it?
It is interesting when people enter a discussion about raising kids, etc and they want to make a case for physically attacking a young person. They'll use cute words, like "spanking," etc.
Some will tell how they were assaulted and how it did them good. Of course, they have no choice, do they, because the parent hitting them was also the person providing food and shelter. People need to think about how disgusting a scenario that is.
It's simply cowardice and an admission that the parent does not know what they are doing so they resort to physical force. And it is quite common, look at the world, people at every level of society, world-wide, are solving their issues with violence and then, when they "win," talking about how "god" was with them, etc.