From what I have read/understand the shifting variable winds/windshear are not solely the problem , but allied to the pretty short runway length they do not leave margins for error.
No room for a displaced threshold
Landing from opposite direction may have a significant tailwind component , short runway, no over run and close to a clip top at far end are problems and 737-8 has had more than a few overrun accidents as readers here know.
Its along trip from Jo'burg and like any Oceanic island a lot can happen to the Weather en route, might be fine to despatch but not good on arrival.
Exploratory fly bys with a herc done some years back are not really replicating behavior of a swept wing jet low down.
Just puzzled someone didnt really make more of an issue of the great big rocks alongside the threshold .
i lived in Bermuda for many years- windy windy windy and runway is 13/31 prevailing and strongest winds , up to 70Kts in winter are from 210-240 and all kinds of airliners and biz jets operate there even though there is high ground close to both approaches. the difference is its dead flat and runway is 10,000 ft plus with benign (to pax if not the aircraft) overuns onto gravel beaches and very shallow water at both ends.
At the end of the day like many complex systems they can tolerate a big deviation from the ideal in one snse (windshear) but not two (windshear and short runway)