While I certainly understand the concern when incidents like this one happen at airports, I am inclined to agree with the spokesperson who is quoted as saying:
"Similar to any branch of this chain, or any other restaurant in a shopping centre or mall, the Spur at JIA is in a public facility.
"While there is a SAPS presence within the airport precinct on an ongoing basis, no form of access control can be put in place in a public facility."
The Spur is land side in the new domestic terminal and is open to the general public. Similarly, at SFO there are restaraunts that are land side, and require no security to approach. Certainly, especially since 9/11 there are many more security personnel, if weapons were concealed, someone armed could go to one of them without prior detection. Getting away once the alarm was raised would be difficult, but probably not impossible.
To get airside at JNB requires a similar screening process to that now used pretty much world wide. I don't think it would be nearly as easy to get to the planes as is implied by the article and discussion.
Security at JNB, and crime in South Africa generally is in fact worse than most developed countries. The South Africa government can and should do a better job of enforcement, and contrary to the tone of the posts before, as a regular traveler to the country, I believe things are improving. There is still a way to go, but somewhat better they are for sure. Both independent and government statistics indicate modest but steady decreases since government started releasing the stats a few years ago. Clearly the most common crimes are those against property, just as they are virtually everywhere. Violent crime, while much higher than Europe or America, is relatively rare.
My work in community and economic development gives me hope that the modest and increasing improvements in opportunity for poor South Africans is helping. The gap is huge still, but I think there is some evidence of the connection between those improvements will help mitigate the crime issues. That definitely does not mean that we should excuse crime by anyone. It is simply my somewhat informed observation.
It shouldn't happen. It is awful, especially when violent, and much work needs to be done. But I don't think this is any huge breach of airport security that imperils people's ablility to travel or implies terrorism is more likely. South Africa is still a terrific place to visit.