You say that as if such opinions should be summarily dismissed. The reality is that physical discipline has many benefits to the child, as it can be used to discourage bad behaviour (hitting other children, etc) and dangerous behaviour (running out into the road, etc). I agree that using physical implements / weapons (belts, objects, etc) is completely unacceptable, no matter the severity of the child's actions. I was smacked when I seriously misbehaved as a child and I believe that it had a positive impact upon me as an individual. It was only ever used on serious occasions and I always knew I was stepping over-the-line. The rest of the time if I misbehaved I was made to stand in a corner and was not allowed to leave until a certain period of time had elapsed (usually about 5-10 minutes). And the latter happened quite a lot, as I had two younger brothers and we would get into fights.
Cue the "I got spanked and I'm fine, so everyone must be fine or is sick from the get-go" trolls...
It's unfair for people to take a report like this and use it to discredit the use of physical discipline when it doesn't take into account the frequency with which it is used. Some of the people in the report noted it occurring on a regular basis, which is really not acceptable - but that should not be compared to a child who is smacked maybe once or twice a year and only when the reason for it is fully explained to them. There has not been enough - if any - research into the benefits of physical discipline. You can't make an informed decision without knowing the evidence for both sides. But judging by the number of unruly children who have clearly never been properly disciplined I cannot fault parents who are only doing what they believe is best for their child. Few would argue that the decline in physical discipline has resulted in better behaved and less troubled children; many would argue the exact opposite.
When I have children I intend to use physical discipline only as a last resort but will not hesitate if I feel it is warranted.