I've never known anyone to say spanking their children was "great." I'm really not seeing anything rational with that statement and unfairly lumping a group of people you disagree with in with child abusers. Spanking should never be the first response to disciplining your child nor should it be a mandatory part of parenting, but if a person can't tell the difference between slapping a child on the wrist because they keep sticking their finger in a light socket after being told not to, and a punching a child in the face, I'm not sure what to tell them. One is for discipline, the other is malicious with the intent of injury. If you're spanking your child to the point of injury, then it's not spanking anymore.
I guess next time my wife slaps me on the wrist for picking at the pot roast, I'll just call the cops on her for abuse. :sarcastic