Tony,
Associate Professor is an American term that is not traditionally used in South Africa, just as we do not term company Directors "Vice Presidents".
The South African version of  thre American term "Associate Professor" is "Senior lecturer".

Perhaps Wits have been subject to American cultural colonisation or imperialism?

In SA, we tend to apply the term "Associate" to people that have not completed their Professional qualifications
Ie Associate member of ABC Professional organisation.

Read the articles by Goerg and Theobald - his papers have mostly been published in B or C grade journals, and his works are very rarely cited.
Theobald suggests that there is possibly a disconnect between what he teaches on campus (makes sense - he has to follow a curriculum) and what appears to be his personal view on normative Economics.