I would say that physical abuse like that is not comparable to a slap. Much fewer people, even in a conservative culture, would approve of disciplining a child that way. Majority would approve of a slap.

Besides, just because you turned out different doesn't mean that majority will, too. I've been belted my entire childhood, but I personally wouldn't do it. Doesn't mean it's become uncommon in general. Usually, people take after their parents.