The good thing is that the comments under that article you posted are all intelligent and blaming the owner, not the dog.
If a guardian breed has a correct temperament, they are not aggressive. They are only supposed to protect in the correct circumstances and yes, they learn what is a dangerous situation and what isn't by proper socialization and training. This rottweiler has a completely incorrect temperament for any breed of dog on the planet. He is not being protective of anything except possibly himself, he is attacking kids because they are there. Most of the rottweilers I meet don't have correct temperament (because most of the ones I meet are bred by BYB for looks), of course, most of them have temperament that is way too friendly, which is fine by me. I'd prefer a dog who is way to friendly to one who is way too suspicious.
That owner should be punished. Are there consequences in South African law for owners who's dogs repeatedly hurt people? If not, there should be!!