Well, for one thing, if you punitively parent a strong-willed child, that child is just going to dig in his heels, making for a wicked adversarial spiral.
I'm sure other mamas have more coherent BTDT things to say, but that's the first thing that came to mind. Oh, and the parent blaming the child for "having" to hit/be harsh. Classic abuse mentality, classic punitive parenting.