There are always two sides to a coin. This article only describes what spanking causes (conveniently listing just bad things). However, there's no mention (or research, for that matter) of how not spanking affects kids, especially if they are prone to doing bad things - parents can only prevent so much, but then kindergarden and elementary school does it's magic
"No mention", except for the part '"There's no study that I've ever done that's found a positive consequence of spanking," Gershoff said.'